Instrument sterile adapter drive features

ABSTRACT

A surgical system ( 200 ) includes a surgical instrument ( 260 ) that is sensitive to backlash that would adversely affect the transmission of controlled torque and position to the surgical instrument. The surgical instrument ( 260 ) is coupled to motors in a surgical instrument manipulator assembly ( 240 ) via a mechanical interface. The combination of the mechanical interface and surgical instrument manipulator assembly ( 240 ) have low backlash, e.g., less than  0.7  degrees. The backlash is controlled in the surgical instrument manipulator assembly ( 240 ). From the drive output disk ( 545 ) in the surgical instrument manipulator assembly to the driven disk ( 964 ) of the surgical instrument, the mechanical interface has zero backlash for torque levels used in surgical procedures.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/911,514 (filed Feb. 11, 2016) (entitled “INSTRUMENT STERILE ADAPTERDRIVE FEATURES”), which is a U.S. national phase of InternationalApplication No. PCT/US2014/051033 (filed Aug. 14, 2014) (entitled“INSTRUMENT STERILE ADAPTER DRIVE FEATURES”), which designated the U.S.and which claims priority to and the benefit of U.S. Patent ApplicationNo. 61/866,120, (filed Aug. 15, 2013) (entitled “INSTRUMENT STERILEADAPTER DRIVE FEATURES”), each of which is incorporated herein byreference in its entirety.

BACKGROUND Field of the Invention

The present invention relates generally to surgical instruments andsystems, and more particularly to surgical instruments with low backlashdrive systems.

Description of Related Art

Robotically controlled systems such as employed for minimally invasivemedical procedures can include large and complex equipment to preciselycontrol and drive relatively small tools or instruments. (As usedherein, the terms “robot” or “robotically” and the like includeteleoperation or telerobotic aspects.) FIG. 1A illustrates an example ofa known robotically controlled system 100. System 100, which may, forexample, be part of a da Vinci® Surgical System commercialized byIntuitive Surgical, Inc., includes a patient-side cart 110 havingmultiple arms 130. Each arm 130 has a docking port 140 that generallyincludes a drive system with a mechanical interface for mounting andproviding mechanical power for operation of an instrument 150. Arms 130can be used during a medical procedure to move and position respectivemedical instruments 150 for the procedure.

FIG. 1B shows a bottom view of a known instrument 150. Instrument 150generally includes a transmission or backend mechanism 152, a main tube154 extending from the backend mechanism 152, and a functional tip 156at the distal end of the main tube 154. Tip 156 generally includes amedical tool such as a scalpel, scissors, forceps, or a cauterizinginstrument that can be used during a medical procedure. Drive cables ortendons 155 connected to tip 156 and extend through main tube 154 tobackend mechanism 152. Backend mechanism 152 typically provides amechanical coupling between the drive tendons of the instrument 150 andmotorized axes of the mechanical interface of a drive system 140. Inparticular, gears or disks 153 have features such as projections orholes that are positioned, sized, and shaped to engage complementaryfeatures on the mechanical interface of a drive system 140. In a typicalinstrument, rotation of disks 153 pulls on respective tendons 155 andactuates corresponding mechanical links in tip 156. System 100 can thuscontrol movement and tension in drive tendons 155 as needed to position,orient, and operate tip 156. Further details of known surgical systemsare described, for example, in U.S. Pat. No. 7,048,745 (filed Aug. 13,2001) to Tierney et al., entitled “Surgical Robotic Tools, DataArchitecture, and Use,” which is hereby incorporated by reference in itsentirety.

Instruments 150 of system 100 can be interchanged by removing oneinstrument 150 from a drive system 140 and then installing anotherinstrument 150 in place of the instrument removed. The installationprocess in general requires that the features on disks 153 properlyengage complementary features of drive system 140. However, beforeinstallation, the orientations of disks 153 on instrument 150 aregenerally unknown to patient-side cart 110.

Further, equipment such as patient-side cart 110 is often covered for amedical procedure by a sterile barrier (e.g., a plastic sheet drape)because of the difficulty in cleaning and sterilizing complex equipmentbetween medical procedures. This sterile barrier can include a sterileadaptor that is interposed between docking port 140 and instrumentbackend 152. See for example, U.S. Pat. No. 7,048,745 and U.S. Pat. No.7,699,855 (filed Mar. 31, 2006) to Anderson et al., entitled “SterileSurgical Adaptor”, which is hereby incorporated by reference in itsentirety, describe some exemplary sterile barrier and adaptor systems.

A typical installation process for an instrument 150 involves mountingbackend mechanism 152 without regard for the orientations of disks 153on a drive system 140, possibly with an intervening sterile adaptor. Thedrive motors in drive system 140 may be then be rotated back and forthmultiple times during the installation procedure to ensure that thecomplementary features mesh with and securely engage each other foroperation of the newly installed instrument 150. At some point duringthe installation process, the drive motors become securely engaged torotate respective disks 153. However, the instrument 150 being installedmay move in an unpredictable manner at times during the installationprocedure because the drive motors positively engage respective disks153 of instrument 150 at different and unpredictable times. For certainapplications, such unpredictable motion is unacceptable. In general,clear or confined space is required around an instrument 150 toaccommodate random movements of the instrument tip during aninstallation procedure.

SUMMARY

A surgical system includes a surgical instrument that is sensitive tobacklash that would adversely affect the transmission of controlledtorque and position to the surgical instrument. The surgical instrumentis coupled to motors in a surgical instrument manipulator assembly via amechanical interface. The combination of the mechanical interface andsurgical instrument manipulator assembly has a low backlash, e.g. lessthan 0.7 degrees. The mechanical interface couples a drive interface inthe surgical instrument manipulator assembly to a driven interface ofthe surgical instrument. The mechanical interface has zero backlash fortorque levels used in surgical procedures, in one aspect.

Thus, an apparatus includes a surgical instrument manipulator assembly.The surgical instrument manipulator assembly includes a drive unit and adrive output assembly. The drive output assembly is coupled to the driveunit. The drive output assembly includes a low backlash coupler coupledto the drive unit. A drive output disk is coupled to the low backlashcoupler. A portion of the surgical instrument manipulator assemblybacklash is in the coupling of the drive unit and the drive output diskto the low backlash coupler.

In one aspect, the drive output disk is a cylindrical body with a distalend surface. A first alignment element extends from the distal endsurface. A second alignment element also extends from the distal endsurface. The first alignment element is separated from the secondalignment element. The combination of the first and second alignmentelements orients the drive output disk to a disk of another assembly inthe apparatus when the drive output disk and the disk are mated. In oneaspect, the first alignment element is a pin, and the second alignmentelement is a tab.

In this aspect, the distal end surface of the drive output disk has acenter and a circumferential edge. A plurality of drive dogs extend fromthe distal end surface. Each drive dog includes a first edge surfacepositioned a first distance from the center, and a second edge surfacepositioned about adjacent to the circumferential edge. The second edgesurface is opposite the first edge surface. Further, each drive dogincludes a first portion that is a three-dimensional structure, e.g., athree-dimensional rectangle, which extends from the distal end surfaceand a second portion that extends from the first portion. The secondportion has two opposing second portion side surfaces. Each of thesecond portion side surfaces is curved surface. In one aspect, thecurved surface is a portion of a circular section, e.g., a portion of anouter surface of a cylinder.

The drive output assembly also includes a shaft. A first preload springis coupled to the shaft. The first preload spring also is coupled to thedrive output disk. The first preload spring is configured to apply afirst preload force on the drive output disk when the first preloadspring is compressed.

The drive output assembly also includes a second preload spring coupledto the shaft. The second preload spring in combination with the firstpreload spring is configured to apply a second preload force on thedrive output disk when the first and second preload springs arecompressed. The second preload force is larger than the first preloadforce.

The surgical instrument manipulator assembly includes a motor packincluding a plurality of drive units. The plurality of drive unitsincludes the drive unit described previously. The motor pack is moveablymounted in a housing of the surgical instrument manipulator assembly.The motor pack also includes a plurality of hard stops. The plurality ofhard stops is configured to extend from a distal face of the motor pack.

The surgical instrument manipulator assembly also includes a releaselatch. The release latch is pivotally mounted in the housing of thesurgical instrument manipulator assembly. A pin extends inside thehousing from a proximal portion of the release latch. In one aspect, thepin is a spring-loaded pin.

The motor pack of the surgical instrument manipulator assembly alsoincludes a release latch inhibit stop. If the motor pack is at a fullywithdrawn position relative to the housing of the surgical instrumentmanipulator assembly, operation of the release latch is not inhibited,in one aspect. However, if the motor pack is at a first positionrelative to the housing, the pin contacts the release latch inhibit stopand prevents pivoting of the release latch if the release latch ispressed. In another aspect, the release latch inhibit stop preventspivoting of the release latch when the motor pack is at the fullywithdrawn position while a surgical instrument is mounted in the sterileadapter assembly.

In another aspect, the apparatus includes a surgical device assembly, apreload track, and a preload assembly riding on the preload track. Thepreload assembly is coupled to the surgical device assembly. Aninsertion assembly includes the preload track.

When the preload assembly is positioned at a first location on thepreload track, the preload assembly applies a first force to thesurgical device assembly. When the preload assembly is positioned at asecond location on the preload track, the preload assembly applies asecond force to the surgical device assembly. The second force is largerthan the first force.

In one aspect, the preload assembly includes a cam follower assembly andan arm. The cam follower assembly rides on the preload track. The armhas a first end and a second end. The first end is coupled to thesurgical device assembly. The second end of the arm is coupled to thecam follower assembly. If the cam follower assembly is positioned at thefirst location on the preload track, the arm is configured to transfer aforce proportional to the first force from the cam follower assembly tothe surgical device assembly. If the cam follower assembly is positionedat the second location on the preload track, the arm is configured totransfer a force proportional to the second force from the cam followerassembly to the surgical device assembly.

The surgical device assembly also includes a drive unit housing and amotor pack. The motor pack is movably mounted in the drive unit housing.The first end of the arm is coupled to the motor pack. If the camfollower assembly is positioned at the first location on the preloadtrack, the arm is configured to transfer a force proportional to thefirst force from the cam follower assembly to the motor pack. If the camfollower assembly is positioned at the second location on the preloadtrack, the arm is configured to transfer a force proportional to thesecond force from the cam follower assembly to the motor pack.

In another aspect, an apparatus includes a preload track and a preloadassembly configured to ride on the preload track. The preload assemblyis configured to couple to a surgical device assembly. The preloadassembly also is configured to apply a first force to the surgicaldevice assembly if the preload assembly is positioned at a firstlocation on the preload track.

The preload assembly includes a preload reset mechanism. The preloadreset mechanism is configured to automatically position the preloadassembly at the first location on the preload track.

In yet another aspect, an apparatus includes a surgical instrumentmanipulator assembly, an insertion assembly, and a preload assembly. Thesurgical instrument manipulator assembly includes a housing and a motorpack. The motor pack is movably mounted in the housing. The insertionassembly is coupled to the surgical instrument manipulator assembly. Theinsertion assembly also includes a preload track. The preload assemblyincludes a cam follower assembly, an arm, and a preload rest assembly.The arm includes a first end and a second end. The first end of the armis rotatably connected to the cam follower assembly. The second end ofthe arm is coupled to the motor pack. The cam follower assembly isconfigured to ride on the preload track. The preload reset assembly isconfigured to automatically position the preload assembly at a firstlocation on the preload track. At the first location, the preloadassembly applies a first force on the motor pack.

Another apparatus includes an insertion assembly, an instrumentmanipulator assembly, a surgical device interface, and a surgicalinstrument. Sometimes, the surgical device interface is referred to as asurgical device interface element. The insertion assembly includes adistal end and a preload track. The instrument manipulator assembly iscoupled to the distal end of the insertion assembly. The instrumentmanipulator assembly includes a drive output disk. The drive output diskhas a drive output interface.

The surgical device interface is mounted on the instrument manipulatorassembly. The surgical device interface includes an intermediate disk.The intermediate disk has an intermediate driven interface and anintermediate drive interface. The intermediate driven interface iscoupled to the drive output interface.

The surgical instrument is mounted on the surgical device interface. Thesurgical instrument includes a driven disk. The driven disk has a driveninterface. The driven interface is coupled to the intermediate driveinterface.

If a first force is applied to the coupling between the drive outputdisk and the intermediate disk, the coupling between the drive outputdisk and the intermediate disk has non-zero backlash for torque levelsused to bring the two disks into alignment. If a second force is appliedto the coupling between the drive output disk and the intermediate disk,the coupling between the drive output disk and the intermediate disk haszero backlash for torque levels used in surgical procedures. The secondforce is larger than the first force.

Thus, the apparatus includes a drive output disk and an intermediatedisk. The drive output disk includes a distal end surface and aplurality of drive dogs extending from the distal end surface. Eachdrive dog of the plurality of drive dogs includes a first portion thatis a three-dimensional structure, e.g., a three-dimensional rectangle,which extends from the distal end surface, and a second portionextending from the first portion. The second portion includes twoopposing second portion side surfaces. Each of the second portion sidesurfaces is a curved surface. In one aspect, the curved surface is aportion of a circular section, e.g., a portion of an outer surface of acylinder. The intermediate disk includes a proximal end surface, and aplurality of drive dog receptacles extending from the proximal endsurface into the intermediate disk. Each drive dog receptacle of theplurality of drive dog receptacles is configured to receive one of theplurality of drive dogs. Each drive dog receptacle of the pluralityincludes a first portion that includes opposed sidewalls extending fromthe outer surface into the intermediate disk, a second portion is abottom surface of the drive dog receptacle, and a third portionextending from the first portion to the second portion. The thirdportion has two opposing third portion sloped side surfaces.

The apparatus has a first preload spring coupled to the drive outputdisk. The first preload spring is compressed when the drive output diskis coupled to the intermediate disk. The compression of the firstpreload spring applies a preload force to the drive output disk. Whenthe preload force is applied to the drive output disk, the couplingbetween the drive output disk and the intermediate disk has non-zerobacklash for torque levels necessary to bring the disks into alignment.

The apparatus also includes a second preload spring coupled to the driveoutput disk. A preload assembly is coupled to the first and secondpreload springs. When the preload assembly compresses the first andsecond preload springs, the compressed second spring in combination withthe compressed first spring applies a second preload force to a couplingbetween the drive output disk and the intermediate disk. When the secondpreload force is applied to the coupling, the coupling between the driveoutput disk and the intermediate disk has zero backlash for torquelevels used in surgical procedures.

In still another aspect, the apparatus includes a surgical deviceinterface element. The surgical device interface element includes aplurality of intermediate disks and a first body structure havingrotatably mounted therein the plurality of intermediate disks.

Each intermediate disk includes an intermediate driven interface and anintermediate drive interface. The intermediate drive interface isopposite from the intermediate driven interface.

The intermediate driven interface includes a first alignment receptacleand drive dog receptacles. The intermediate drive interface includesdrive dogs and an engagement structure.

The first alignment receptacle is configured to mate with a firstalignment element extending from a drive output disk of a surgicalinstrument manipulator assembly. The intermediate driven interface alsoincludes a second alignment receptacle. The second alignment receptacleis configured to mate with a second alignment element extending from thedrive output disk. The first alignment receptacle is separated from thesecond alignment receptacle. The combination of the first and secondalignment receptacles orients the drive output disk to the intermediatedisk when the drive output disk and the intermediate disk are coupled,e.g., mated.

The first body structure includes a plurality of hard stops. Eachintermediate disk is associated with one of the hard stops. Eachintermediate disk has a hard stop tab extending from an outer sidesurface of that disk. In a first axial position of the intermediatedisk, the hard stop tab contacts the hard stop associated with theintermediate disk when the intermediate disk is rotated. In a secondaxial position of the intermediate disk, the intermediate disk rotatesfreely without the hard stop tab contacting the hard stop associatedwith the intermediate disk.

Each of the drive dog receptacles includes a first portion havingopposed sidewalls extending from an outer surface of the intermediatedisk into the intermediate disk. A second portion of the drive dogreceptacle is a bottom surface of the drive dog receptacle. A thirdportion of the drive dog receptacle extends from the first portion tothe second portion. The third portion includes two opposing thirdportion side surfaces. Each of the third portion side surfaces is asloped surface. In one aspect, the sloped surface is a portion of a sidesurface of a wedge.

Each of the drive dogs of the intermediate disk has a first portion thatis a three-dimensional structure, e.g., a three-dimensional rectangle. Asecond portion of the drive dog extends from the first portion. Thesecond portion has two opposing second portion side surfaces. Each ofthe second portion side surfaces is a portion of curved surface. In oneaspect, the curved surface is a portion of a circular section, e.g., aportion of an outer surface of a cylinder.

Each of the drive dog receptacles of the intermediate disk is positionedso that each of the drive dog receptacles is bisected by a first plane.Each of the drive dogs of the intermediate disk is positioned so thateach of the drive dogs is bisected by a second plane. The first plane isperpendicular to the second plane.

The surgical device interface element also includes a second bodystructure. The first body structure is movably mounted in the secondbody structure. The second body structure includes a skid plate.

The intermediate disk also has a distal surface. The engagementstructure, in one aspect, is an open three-dimensional structureextending in a distal direction from the distal surface. The openthree-dimensional structure is a generally C-shaped structure. TheC-shaped structure has a height, a first end, and a second end. Thefirst and second ends bound an opening of the C-shaped structure. Acenterline extends through a center of the C-shaped structure. Thecenterline is equidistance from the first and second ends.

The open three-dimensional structure also includes a wall extending fromone of the first and second ends. The wall extends in a directionsubstantially parallel to the centerline of the C-shaped structure. Thewall also extends towards an outer edge of the distal surface of theintermediate disk. The wall has a height that is smaller than the heightof the C-shaped structure.

In another aspect, the open three-dimensional structure is a circulartrack. The circular track includes a first circumferential sectionhaving a first height, a first end, and a second end. The circular trackalso includes a second circumferential section extending between thefirst and second ends of the first circumferential section. The secondcircumferential section has a second height. The second height is lessthan the first height. A centerline of the circular tracks extendsthrough a center of the circular track and is equidistance from thefirst and second ends. The C-shaped structure is an example of thecircular track. In this aspect, the open three-dimensional structurealso includes a wall extending in a direction substantially parallel tothe centerline of the circular section from one of the first and secondends of the first circumferential section. The wall extends towards anouter edge of the distal surface of the intermediate disk of theplurality of intermediate disks. The wall has a height. The height ofthe wall is smaller than the first height of the first circumferentialsection.

In one aspect, the surgical device interface element is mounted on asurgical instrument manipulator assembly. The surgical instrumentmanipulator assembly includes a drive output disk having a driveinterface. The drive interface is coupled with the intermediate driveninterface of the intermediate disk. Upon applying a predeterminedpreload force to the drive output disk, the coupling between theintermediate disk and the drive output disk has zero backlash for torquelevels used in surgical procedures.

In another aspect, a surgical instrument is mounted on the surgicaldevice interface element. The surgical instrument further has a drivendisk with a driven interface. The driven interface is coupled to theintermediate drive interface of the intermediate disk. Upon applying apredetermined preload force to the intermediate disk, the couplingbetween the intermediate disk and the driven disk has zero backlash fortorque levels used in surgical procedures.

Thus, in one aspect, the apparatus includes an intermediate disk and adriven disk. The intermediate disk includes an intermediate driveninterface and an intermediate drive interface. The intermediate driveinterface is opposite from the intermediate driven interface.

The intermediate driven interface includes an alignment receptacle anddrive dog receptacles. The intermediate drive interface includes drivedogs and an engagement structure.

The driven disk includes a driven interface configured to mate with theintermediate drive interface. The driven interface includes anengagement receptacle, drive dog receptacles, and a rotation disableelement. The rotation disable element includes a rotation lockingmechanism that prevents rotation of the driven disk. The engagementreceptacle is configured to receive the engagement structure if theengagement structure is aligned with the engagement receptacle.

In still yet a further aspect, the apparatus includes a surgicalinstrument. The surgical instrument includes a body that has a drivendisk receptacle. A proximal end of a shaft, which is in the surgicalinstrument, extends into the driven disk receptacle. A driven disk ismounted on the proximal end of the shaft so that the driven disk ispositioned in the driven disk receptacle.

The driven disk includes a driven interface. The driven interfaceincludes an engagement receptacle, drive dog receptacles, and a rotationdisable element. The rotation disable element has a rotation lockingmechanism. Upon engagement of the rotation disable element, the rotationlocking mechanism engages the driven disk receptacle and preventsrotation of the driven disk.

Each of the drive dog receptacles includes a first portion, a secondportion, and a third portion. The first portion includes opposedsidewalls extending from a proximal surface of the driven disk into thedriven disk. The second portion is a bottom surface of the drive dogreceptacle. The third portion extends from the first portion to thesecond portion. The third portion has two opposing third portion sidesurfaces. Each of the third portion side surfaces includes a slopedsurface. In one aspect, the sloped surface is a portion of a sidesurface of a wedge. In one aspect, each drive dog receptacle includes afirst edge surface positioned a first distance from a longitudinal axisof the driven disk, and a second open edge opposite the first edge.

The engagement receptacle includes a groove extending from a proximalsurface of the driven disk into the driven disk. The groove extends froma first end to a second end. The groove has a width and a depth. Thefirst end of the groove is separated from the rotation disable elementby a first gap. The second end of the groove is separated from therotation disable element by a second gap. The width and depth of thegroove is sized to accept an engagement structure of an intermediatedrive interface on an intermediate disk.

In one aspect, the rotation disable element is a flexure. The rotationlocking mechanism extends from the flexure. In this aspect, the rotationlocking mechanism includes a tang.

The driven disk receptacle has a bottom surface. A plurality of teethextends in a proximal direction from the bottom surface.

The apparatus also includes a sterile adapter assembly. The surgicalinstrument is mounted on the sterile adapter assembly. The sterileadapter assembly includes an intermediate disk having an intermediatedrive interface coupled with the driven interface of the driven disk.Upon applying a predetermined preload force to the intermediate disk,the coupling between the intermediate disk and the driven disk has zerobacklash.

The apparatus also includes a surgical instrument manipulator assembly.The sterile adaptor assembly is mounted on the surgical instrumentmanipulator assembly. The surgical instrument manipulator assemblyfurther includes a drive output disk having a drive interface coupledwith the driven interface of the intermediate disk. Upon applying thepredetermined preload force to the drive output disk, the couplingbetween the intermediate disk and the drive output disk has zerobacklash for torque levels used in surgical procedures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an illustration of a prior art teleoperated minimallyinvasive surgical system.

FIG. 1B is an illustration of a prior art surgical device assembly.

FIG. 2 is an illustration of a teleoperated surgical system thatincludes a surgical device assembly with a low backlash.

FIG. 3A is a more detailed illustration of the configuration of thesurgical device assemblies in FIG. 2, where a surgical device assemblyhas a low backlash.

FIG. 3B is a more detailed illustration of the configuration of thesurgical device assemblies in FIG. 2, where a surgical device assemblyhas a low backlash.

FIGS. 4A to 4G are block diagrams that illustrate the mounting of asterile adapter assembly and a surgical instrument on a surgicalinstrument manipulator assembly, operation of preload mechanism toreduce backlash, instrument removal lockout, sterile adapter removallockout, preload release, and automatic preload reset.

FIG. 5 illustrates a distal end of the surgical instrument manipulatorassembly of FIG. 2.

FIG. 6 illustrates the surgical instrument manipulator assembly affixedto an insertion assembly that in turn is attached to an insertion axisbase assembly.

FIGS. 7A and 7B illustrate a first aspect in attaching a sterile adapterassembly to the surgical instrument manipulator assembly.

FIG. 8A illustrates another aspect of a drive output unit and a sterileadapter assembly.

FIGS. 8B to 8D are cut-away drawings illustrating the coupling of thesterile adapter assembly of FIG. 8A to the drive output unit.

FIGS. 8E to 8G are cut-away drawings illustrating a sterile adapterlatch assembly for the sterile adapter assembly of FIG. 8A.

FIG. 8H is bottom perspective view of the sterile adapter assembly ofFIG. 8A.

FIG. 8I is a top perspective view of the sterile adapter assembly ofFIG. 8A.

FIGS. 9A and 9B are more detailed illustrations of the surgicalinstrument of FIG. 2.

FIGS. 10 to 13 illustrate stages in the mounting of the surgicalinstrument in the sterile adapter assembly.

FIG. 14 is an illustration of a disk stack when a drive output disk iscoupled, e.g., mated, to an intermediate disk and the intermediate diskis coupled to a driven disk.

FIG. 15A is an illustration of the surgical instrument manipulatorassembly with the drive unit assembly housing removed and with thehousing around the drive output unit removed.

FIG. 15B is a side view of a planetary gearhead.

FIG. 15C is a distal view of the planetary gearhead.

FIG. 15D is a proximal view of a 28:1 planetary gearhead.

FIG. 15E is a proximal view of a 9:1 planetary gearhead.

FIG. 16A is a more detailed illustration of the drive output assembly.

FIG. 16B is an end view of the low backlash coupler.

FIG. 16C is an illustration of a drive interface on the drive outputdisk.

FIG. 16D is a cross-sectional view of a drive dog.

FIG. 17A is an illustration of the sterile adapter assembly.

FIG. 17B is an enlarged illustration of a portion of the movable bodyshowing a receptacle and an intermediate disk.

FIG. 18A is an illustration of the intermediate driven interface on theproximal end of the intermediate disk.

FIG. 18B is an illustration of the intermediate drive interface on thedistal end of the intermediate disk.

FIG. 18C is a cross-sectional view of a drive dog receptacle.

FIG. 18D is a cross sectional view that illustrates a drive dog insertedin a drive dog receptacle under the light preload force after the driveinterface on the drive output disk has partially coupled with theintermediate driven interface on the intermediate disk.

FIG. 19A is an illustration of the driven interface on a proximal end ofthe driven disk.

FIG. 19B is an illustration of a part of the body of the driveninterface assembly.

FIG. 20A illustrates a cut-away view of when the intermediate disk andthe driven disk are in contact, i.e., partially coupled, but are notmated.

FIG. 20B illustrates a cut-away view of when the intermediate disk andthe driven are mated.

FIG. 21 is a more detailed illustration of one aspect of the insertionassembly.

FIGS. 22A and 22B illustrate a preload assembly in greater detail.

FIG. 22C is a free body force diagram of the forces acting on a wheel inthe cam follower assembly of the preload assembly.

FIGS. 22D and 22E show that a motor pack has moved an additionaldistance A relative to the top of the drive unit housing that moveddistance Zload.

FIG. 22F illustrates, in one aspect, dimensions of the preload track.

FIG. 22G is a graph of a retraction force versus insertion distance of asurgical instrument.

FIG. 23 is a more detailed illustration of the preload assembly.

FIG. 24A illustrates release of the cam follower assembly.

FIG. 24B illustrates an automatic preload reset mechanism of the preloadassembly.

FIG. 25 is a cut-away view of a surgical instrument manipulatorassembly, a sterile adapter assembly, and a surgical instrument, and themotor pack of the surgical instrument manipulator assembly includes aplurality of deployed hard stops.

FIGS. 26A and 26B are illustrations of a release latch mechanism and amechanism to inhibit operation of the release latch mechanism.

In the drawings, for single digit figure numbers, the first digit in thereference numeral of an element is the number of the figure in whichthat element first appears. For double-digit figure numbers, the firsttwo digits in the reference numeral of an element is the number of thefigure in which that element first appears.

DETAILED DESCRIPTION

In one aspect, a surgical system 200 (FIG. 2), e.g., a minimallyinvasive teleoperated surgical system, includes a patient-side cart 210having an arm 220. At an end of arm 220 is an entry guide manipulator230. Mounted on entry guide manipulator 230 is a master instrumentmanipulator 280 that in turn supports multiple surgical deviceassemblies. In one aspect, a surgical device assembly includes asurgical instrument manipulator assembly 240, an instrument sterileadapter assembly 250, and a surgical instrument 260.

Surgical instrument manipulator assembly 240 is sometimes referred to asinstrument manipulator assembly 240. Instrument sterile adapter assembly250 is sometimes referred to as sterile adapter assembly 250.

Entry guide manipulator 230 changes the pitch and yaw of the surgicaldevice assemblies as group. A main tube of each surgical instrument 260extends through a different channel in a single port entry guide 270.Single port entry guide 270 is mounted in a cannula, in this aspect.Single port refers to a single access location (e.g., a single incision,a single natural orifice, and the like) to a surgical site inside thepatient.

As used herein, a cannula is a tube that passes through the patient'sbody wall, and that comes in direct contact with the patient. Thecannula generally does not slide in and out relative to the patient, butthe cannula can pitch and yaw around a point on its axis called theremote center of motion.

As used herein, singe port entry guide 270 is a tube through which allsurgical instruments and a camera instrument must pass to reach alocation inside the patient. Entry guide 270 has separate lumens foreach instrument. Entry guide 270 passes through the cannula, and maytwist relative to the cannula.

As used here, backlash is a maximum angle through which one part of amechanical interface can be moved without moving a connected part of themechanical interface. Surgical instrument 260 is sensitive to backlashthat would adversely affect the transmission of controlled torque andposition from instrument manipulator assembly 240 to surgical instrument260. As explained more completely below, surgical instrument 260 iscoupled to motors in instrument manipulator assembly 240 via amechanical interface. The combination of the mechanical interface andinstrument manipulator assembly 240 has low backlash, e.g., less than0.7 degrees. From the output disk (the drive output disk) in instrumentmanipulator assembly 240 to the input disk (the driven disk) of surgicalinstrument 260, the mechanical interface has zero backlash, in oneaspect.

In one aspect, the mechanical interface includes sterile adapterassembly 250. Sterile adapter assembly 250 includes a sterile drape (notshown). The sterile drape is configured in a matter equivalent to theconfigurations known to those knowledgeable in the field. Sterileadapter assembly 250 is a single use product. Therefore, the portion ofthe mechanical interface implemented in sterile adapter assembly 250includes a minimal number of parts, as described more completely below.

A transmission unit of surgical instrument 260 has multiple parallelinput shafts. Due to manufacturing variations and tolerances, not all ofthese input shafts are or can be perfectly parallel or preciselylocated. For this reason, the mechanical interface must accommodateshaft angular and planar misalignment during the process of engagingsurgical instrument 260 to instrument manipulator assembly 240. Themechanical interface couples surgical instrument 260 to the drive motorsin instrument manipulator assembly 240 with very little, effectivelyzero, instrument tip motion during the instrument engagement process. Asexplained more completely below, until surgical instrument 260 isengaged with the motors in instrument manipulator assembly 240,instrument tip motion is inhibited. In addition, the distal end ofsurgical instrument 260 does not extend beyond the distal end of thecannula until the backlash in the mechanical interface has beenminimized.

A controller 290 is coupled to a surgeon's control console (not shown)and to patient-side cart 210. Controller 290 represents the variouscontrollers in system 200. Controller 290 sends control commands to thesurgical instrument 260 in response to control commands. The controlcommands are based on movements of masters in a surgeon's controlconsole by a surgeon. A display module in system controller 290 alsoupdates a stereoscopic view of the surgical site generated by a displaydevice in the surgeon's control console as slave surgical instrument 260moves in response to the control commands.

Although described as controller 290, it is to be appreciated thatcontroller 290 may be implemented in practice by any combination ofhardware, software that is executed on a processor, and firmware. Also,its functions, as described herein, may be performed by one unit ordivided up among different components, each of which may be implementedin turn by any combination of hardware, software that is executed on aprocessor, and firmware. When divided up among different components, thecomponents may be centralized in one location or distributed acrosssystem 200 for distributed processing purposes. A processor should beunderstood to include at least a logic unit and a memory associated withthe logic unit.

FIGS. 3A and 3B are illustrations of four surgical device assemblies 300mounted on entry guide manipulator 230. In FIG. 3A, surgical deviceassemblies 300 are positioned at an initial position, e.g., a firstlocation. As explained more completely below, the mechanical interfaceincludes a disk stack between a motor in instrument manipulator assembly240 and a shaft in the transmission unit of surgical instrument 260. Inthe configuration of FIG. 3A, a first preload force is applied on thedisk stack, e.g., a first predetermined force is applied on the diskstack.

With this first preload force, the mechanical interface may have somebacklash because the first preload force is not sufficient to clamp thedisks in the disk stack tightly enough together to prevent relativemotion between the disks in the mechanical interface. However, thedesign of disks in the disk stack in the mechanical interface incombination with the first preload force ensures that the disks in thedisk stack remain engaged, e.g., partially coupled, until the backlashis minimized.

With the first preload force, which is a low preload force, the disks inthe mechanical interface have zero backlash up to a first torque level,e.g., 1.17 in-lb assuming a friction coefficient of 0.1. Above the firsttorque level, there may be a known small backlash, for example 1.13degrees. Since, as described more completely below, a force sufficientto spin the disks to overcome friction and dynamically mate the disksquickly is used, this force typically provides more than the firsttorque level. In this instance, the disks in the mechanical interfacehave non-zero backlash. Thus, the mechanical interface is said to havenon-zero backlash in this instance.

In FIG. 3B, three of the four surgical device assemblies have been moveddistally. Arrow 390 defines the distal and proximal directions. Here,the distal direction is towards patient 201 and away from masterinstrument manipulator 280. The proximal direction is away from patient201 and towards master instrument manipulator 280.

As surgical device assembly 300 moves distally on insertion assembly331, the preload force on the disk stack is automatically increased fromthe first preload force to a second preload force. The second preloadforce is an example of a second predetermined force. The second preloadforce reduces the backlash of the mechanical interface, i.e., thebacklash between the disks in the disk stack, to zero for torque levelsused in surgical procedures.

In one aspect, the second preload force is a high preload force, e.g.,2.3 lb. As just described, the disks in the mechanical interface, andhence the mechanical interface, have zero backlash at torque levels usedin surgical procedures. In one example if the coefficient of friction isassumed to be 0.1, the mechanical interface has zero backlash for torquelevels up to 4.9 in-lb. For surgical instrument 260 to apply surgicallyuseful forces at the end effector a certain torque must be applied tothe disks in the mechanical interface. This is deemed a surgicallyuseful torque. In one example, a surgically useful torque may be 4.425in-lb, and so the mechanical interface has zero backlash for torquelevels used in surgical procedures in this aspect.

As explained more completely below, unlike the prior art, the control ofthe backlash is in instrument manipulator assembly 240. Previously, thebacklash was controlled in a sterile adapter assembly that wasdisposable, which in one instance required that the sterile adapterassembly include injection-molded parts that had resilient properties.Moving control of the backlash into instrument manipulator assembly 240allows use of machined parts, and so allows reduction of the backlash.

FIGS. 4A to 4G are block diagrams that illustrate the mounting of asterile adapter assembly and a surgical instrument on a surgicalinstrument manipulator assembly. Other aspects illustrated in FIGS. 4Ato 4G include operation of a preload mechanism to reduce backlash,instrument removal lockout, sterile adapter removal lockout, preloadrelease, and automatic preload reset. FIGS. 4A to 4G are not to scale.Arrow 390 in FIGS. 4A and 4G shows the proximal and distal directions ineach of FIGS. 4A to 4G.

FIG. 4A shows a surgical instrument manipulator assembly 440 affixed toinsertion assembly 431. In particular, instrument manipulator assemblyhousing 448 is fixedly attached to a distal end of insertion assembly431, and so instrument manipulator assembly housing 448 moves withmovement of insertion assembly 431. However, a motor pack 446 withininstrument manipulator assembly housing 448 can move on rail 439. Motorpack 446 can move in the distal and proximal directions relative toinstrument manipulator assembly housing 448. Motor pack 446 is coupledto instrument manipulator assembly housing 448 by a return spring 447.

Motor pack 446 is movably coupled to insertion assembly 431 by preloadassembly 480. Preload assembly 480 rides on a preload track in insertionassembly 431. As explained more completely below, as preload assembly480 moves in the distal direction, preload assembly 480 provides alongitudinal force in the distal direction on motor pack 446. Preloadassembly 480 includes a preload release button 482.

Motor pack 446 includes a plurality of drive units 441. Plurality ofdrive units 441 includes a plurality of drive motors and a plurality ofdrive output assemblies. Each drive motor in the plurality of drivemotors is coupled to a corresponding drive output assembly 443 in theplurality of drive output assemblies.

Drive output assembly 443 includes a preload spring assembly and a driveoutput disk 445. Drive output assembly 443 also includes a low backlashcoupler positioned between the preload spring assembly and drive outputdisk 445. Drive output disk 445 is coupled to the low backlash couplerby a set of input pins. As explained more completely below, drive outputdisk 445 is a cylindrical disk that includes a distal end surface. Thedistal end of each drive output disk 445 has a drive interface. Thedrive interface includes drive dogs and alignment elements.

The drive dogs extend in a distal direction from the distal end surface.Each drive dog includes a first portion comprising a three-dimensionalstructure, e.g., a three-dimensional rectangle, which extends from thedistal end surface and a second portion extending from the firstportion. The second portion of the drive dog includes two opposingsecond portion side surfaces, and each of the second portion sidesurfaces includes a curved surface. In one aspect, the curved surface isa portion of a circular section, e.g., a portion of an outer surface ofa cylinder.

Motor pack 446 includes a plurality of hard stops 437 configured toextend from a distal face of motor pack 446, and motor pack 446 alsoincludes a release latch inhibit stop 438. Release latch inhibit stop438 extends in the distal direction from one side of motor pack 446. Arelease latch 435 is mounted in a wall of instrument manipulatorassembly housing 448. A latch pin 435P is coupled to a proximal portionof release latch 435.

FIG. 4A shows instrument manipulator assembly 440 with the preloadreleased, e.g., motor pack 446 is at a fully withdrawn position. In thisconfiguration, return spring 447 retracts motor pack 446 withininstrument manipulator assembly housing 448 so that the plurality ofdrive output disks including drive output disk 445 do not extend from adistal face of instrument manipulator assembly housing 448. The distalface of motor pack 446 is at position 432, which is the fully withdrawnposition.

In one aspect, when motor pack 446 is located at fully withdrawnposition 432, controller 290 causes insertion assembly 431 to move thepreload track on which preload assembly 480 rides. The movement of thepreload track results in preload assembly 480 applying a longitudinalforce on motor pack 446. The longitudinal force on motor pack 446 movesmotor pack 446 distally relative to instrument manipulator assemblyhousing 448 to position 433 so that the plurality of drive output disksincluding drive output disk 445 extend from the distal face ofinstrument manipulator assembly housing 448, as illustrated in FIG. 4B.With motor pack 446 at position 433, return spring 447 is stretched fromits initial state when motor pack 446 was at position 432.

A surgical device interface element 450, e.g., a sterile adapter, couldbe mounted on instrument manipulator assembly 440 configured as shown inFIG. 4B. However, mounting the surgical device interface element 450 inthis configuration requires compressing the plurality of preload springassemblies including the preload spring assembly in drive outputassembly 443 during the mounting process.

Thus, in one aspect, if motor pack 446 is in the position illustrated inFIG. 4B, prior to mounting surgical device interface element 450,preload release button 482 is activated so that the first longitudinalforce applied on motor pack 446 by preload mechanism 408 is released.Consequently, return spring 447 pulls motor pack 446 to fully withdrawnposition 432, as illustrated in FIG. 4A.

With motor pack 446 in fully withdrawn position 432, in one aspect,tongues on one end of surgical device interface element 450 arepositioned in grooves in instrument manipulator assembly housing 448 andthe other end of surgical device interface element 450 is moved in theproximal direction until that other end engages with release latch 435as shown in FIG. 4C. In the configuration of FIG. 4C with motor pack 446fully withdrawn, if the proximal end of release latch 435 is pushed,release latch 435 releases surgical device interface element 450, andsurgical device interface element 450 can be removed from instrumentmanipulator assembly 440. However, in one aspect, if a surgicalinstrument is mounted in surgical device interface element 450 whilemotor pack 446 is in the fully withdrawn position 432, operation ofrelease latch 435 is inhibited by release latch inhibit stop 438 untilafter preload release button 482 is pressed, e.g., is activated.

Thus, in this aspect, a surgical device interface element 450 (FIG. 4C)is mounted on the distal face of instrument manipulator assembly 440. Asexplained more completely below, surgical device interface element 450includes a frame 451 and a movable body 451C. Moveable body 451C canmove in the proximal and distal directions within frame 451. A pluralityof intermediate disks is mounted in moveable body 451C so that each ofthe plurality of intermediate disks can rotate relative to frame 451. Inthis aspect, each intermediate disk in the plurality of disks is thesame, and so intermediate disk 453 is representative of each of theplurality of intermediate disks.

Each intermediate disk 453 of the plurality of intermediate disksincludes an intermediate driven interface 455, a first intermediate diskinterface, and an intermediate drive interface 456, a secondintermediate disk interface. Intermediate driven interface 455 isopposite and removed from intermediate drive interface 456. In oneaspect, as explained more completely below, intermediate driveninterface 455 includes a first alignment receptacle and drive dogreceptacles. Intermediate drive interface 456 includes drive dogs and anengagement structure.

Each of the drive dog receptacles of the intermediate driven interfaceis positioned so that each of the drive dog receptacles of theintermediate driven interface is bisected by a first plane. Each of thedrive dogs of the intermediate drive interface is positioned so thateach of the drive dogs of the intermediate drive interface is bisectedby a second plane. The first plane is perpendicular to the second plane.

Each of the drive dog receptacles of the intermediate driven interfaceincludes a first portion comprising opposed sidewalls extending from theouter surface into the intermediate disk, a second portion comprising abottom surface, and a third portion extending from the first portion tothe second portion. The third portion includes two opposing thirdportion side surfaces, where each third portion side surface includes asloped surface.

Each of the drive dogs of the intermediate drive interface includes afirst portion and a second portion extending from the first portion. Thefirst portion is a three-dimensional structure, e.g., athree-dimensional rectangle. The second portion includes two opposingsecond portion side surfaces, where each second portion side surfaceincludes a curved surface. The engagement structure includes an openthree-dimensional structure extending in a distal direction from thedistal surface of the intermediate disk.

Movable body 451C also includes a plurality of hard stop receptacles457. Plurality of hard stop receptacles 457 extend from a proximal faceof movable body 451C in a distal direction into movable body 451C.

In one aspect, instrument manipulator assembly 440 includes a sensorthat sends a signal to controller 290 when surgical device interfaceelement 450 is mounted on instrument manipulator assembly 440. Inresponse to this signal, controller 290 causes insertion assembly 431 tomove the preload track on which preload assembly 480 rides so thatpreload assembly 480 is reset and so that preload assembly 480automatically applies the longitudinal force on motor pack 446. Thelongitudinal force on motor pack 446 moves motor pack 446 distallyrelative to instrument manipulator assembly housing 448 to position 433.

As motor pack 446 is moved from fully withdrawn position 432 to position433, a drive interface of each drive output disk 445 of the plurality ofdrive output disks contacts a corresponding intermediate driveninterface 455 of the plurality of intermediate driven interfaces of theplurality of intermediate disks and in turn, each intermediate disk 453contacts movable body 451C. When movable body 451C moves distally as faras possible within frame 451, further motion of drive output disk 445 inthe distal direction is inhibited.

Consequently, as motor pack 446 continues to move to position 433, inresponse to the longitudinal force, return spring 447 is stretchedfurther, and the preload spring assembly in each drive output assembly443 of the plurality of drive output assemblies is compressed so that apreload force is exerted on each drive output disk 445 in the pluralityof drive output disks. The preload force pushes against drive outputdisk 445 and against a corresponding intermediate driven interface 455so that the preload force is transferred to each intermediate disk 453of the plurality of intermediate disks in surgical device interfaceelement 450. This configuration is illustrated in FIG. 4D.

When surgical device interface element 450, sometimes referred to as asurgical device interface, is first mounted on instrument manipulatorassembly 440, the elements of intermediate driven interface 455 may notbe aligned with corresponding elements of the drive interface on driveoutput disk 445. If the elements of disks 453 and 445 are not aligned,the two disks are partially coupled together by features in the driveand intermediate driven interfaces, but the two disks are not coupled,e.g., mated, to each other.

Next, controller 290 sends a signal to instrument manipulator assembly440 to rotate drive output disk 445. As explained more completely below,rotation of intermediate disk 453 is inhibited and drive output disk 445is rotated until the drive interface of drive output disk 445 mates withintermediate driven interface 455 of intermediate disk 453. Also, asexplained more completely below, the partial coupling of the elements ofthe drive interface on drive output disk 445 with the correspondingelements of intermediate driven interface 455 on intermediate disk 453assures that the two disks remain partially coupled under the preloadforce as the two disks rotate. In one aspect, when the two disks arecoupled, another sensor detects a change in a height of the disk stackand sends a signal to controller 290 to stop the rotation of driveoutput disk 445. An alternative technique to sense the mating of the twodisks is described below. When the two disks are mated, the preloadforce is reduced, because the height of the disk stack is reduced.

When motor pack 446 is at position 433, release latch inhibit stop 438extends in front of latch pin 435P that is coupled to release latch 435.Thus, if someone tries to release surgical device interface element 450by pressing on the proximal end of release latch 435, latch pin 435Pcontacts release latch inhibit stop 438, which prevents releasingsurgical device interface element 450, because release latch 435 cannotbe pivoted enough to release surgical device interface element 450.Thus, while there is a preload force on surgical device interfaceelement 450, surgical device interface element 450 cannot be dismounted.

In another aspect, when surgical device interface element 450 is mountedon instrument manipulator assembly 440, a signal is not sent to thecontroller and so motor pack 446 remains at fully released position 432,as illustrated in FIG. 4C. A surgical instrument 460 can be coupled toinstrument manipulator assembly 440 in either the configuration of FIG.4B, or the configuration of 4C. For purposes of an example, theconfiguration of FIG. 4C is used.

In one aspect, a first end of surgical instrument 460 is slid along aramp in frame 451 of surgical device interface element 450 untilsurgical instrument 460 is held in the proper position, as illustratedin FIG. 4E. In one aspect, surgical instrument 460 includes a body 465and a main tube 467. Main tube 467 extends distally from body 465. Body465 includes a driven disk receptacle 463, a shaft 466, and a drivendisk 464. Shaft 466 and driven disk 464 are part of a transmission unitthat transmits received torque through the instrument to one or morecomponents of the instrument.

A proximal end of shaft 466 extends into driven disk receptacle 463, anddriven disk 464 is mounted on the proximal end of shaft 466 so thatdriven disk 464 is positioned in driven disk receptacle 463. Driven disk464 includes a driven interface that interfaces with intermediate driveinterface 456 of intermediate disk 453.

The driven interface of driven disk 464 includes an engagementreceptacle, drive dog receptacles, and a rotation disable element. Thedrive dog receptacles are equivalent to those described above. Therotation disable element includes a rotation locking mechanism. Uponengagement of the rotation disable element, the rotation lockingmechanism engages driven disk receptacle 463 and prevents rotation ofdriven disk 464.

When surgical instrument 460 is coupled to instrument manipulatorassembly 440, each driven disk 464 pushes a corresponding intermediatedisk 453 in surgical device interface element 450 proximally so thatintermediate disk 453 can rotate freely. This increases the preloadforce on the disk stack. However, when surgical instrument 460 is firstmounted on surgical device interface element 450, the elements ofintermediate drive interface 456 may not be aligned with correspondingelements of the driven interface on driven disk 464. If the elements ofthe two disks 453 and 464 are not aligned, the two disks are partiallycoupled together by features in intermediate drive interface 456 and inthe driven interface, but the two disks are not mated to each other.

As explained more completely below, when intermediate drive interface456 of an intermediate disk 453 is not aligned with the correspondingdriven interface of driven disk 464, an engagement structure onintermediate drive interface 456 of intermediate disk 453 engages arotation disable element on driven disk 464 of surgical instrument 460.The rotation disable element includes a rotation locking mechanism. Uponengagement of the rotation disable element, the rotation lockingmechanism engages driven disk receptacle 463 and prevents rotation ofdriven disk 464.

When surgical instrument 460 is coupled to instrument manipulatorassembly 440, instrument manipulator assembly 440 detects the presenceof surgical instrument 460, and sends a signal to controller 290. Inresponse to the signal, controller 290 sends a signal to instrumentmanipulator assembly 440 to rotate drive output disk 445. As theintermediate drive interface 456 of intermediate disk 453 rotates withdriven disk 464 fixed in place, each element on intermediate driveinterface 456 rotates into alignment with the corresponding element ofthe driven interface of driven disk 464 and mates with the correspondingelement. The coupling of intermediate drive interface 456 and the driveninterface on driven disk 464 releases the rotation lock on driven disk464. Thus, the stack of disks, disks 445, 453, and 464, rotates as aunit. When disks 453 and 464 are coupled, the sensor again detects achange in a height of the disk stack and sends a signal to controller290 to stop the rotation of drive output disk 445. When the stack ofdisks is mated, the preload force applied to the disk stack is referredto as a first longitudinal force, i.e., a first preload force.

The above description assumed that surgical instrument 460 was mountedwith instrument manipulator assembly 440 and surgical device interfaceelement 450 in the configuration illustrated in FIG. 4D. However, in adifferent aspect, if the instrument manipulator assembly 440 andsurgical device interface element 450 were in the configurationillustrated in FIG. 4C, when surgical instrument 460 is mounted, thesensor sends the signal to the controller and the controllerautomatically resets the preload, as described above so that disks 445,453, and 464 are under the preload force. The controller then rotatesdrive output disk 445 so that the stack of disks are aligned, becomemated, and rotates as a unit, in a manner equivalent to that describedabove. Therefore, irrespective of the initial position of motor pack 446with respect to positions 432 and 433 when surgical instrument 460 ismounted, the resulting configuration is shown in FIG. 4E.

In the configuration of FIG. 4E with the first longitudinal forceapplied to motor pack 446, surgical device interface element 450 cannotbe removed without releasing the preload. However, surgical instrument460 could still be removed. As explained more completely below, in oneaspect, there are release buttons on each side of surgical instrument460. Engaging the release buttons causes a mechanism in surgicalinstrument 460 to push movable body 451C in surgical device interfaceelement 450 proximally so that intermediate disk 453 and driven disk 464are disengaged and surgical instrument 460 can be removed.

As surgical instrument 460 is inserted into a cannula by movinginstrument manipulator assembly 440 along insertion assembly 431, asecond preload force is applied on the disk stack of disks 445, 453, and464 by preload assembly 480 before an end component coupled to main tube467 protrudes from a distal end of the cannula. Specifically, assurgical instrument 460 moves distally, preload assembly 480 movesdistally along the preload track. As explained more completely below,when instrument manipulator assembly 440 moves distally a predetermineddistance Zload, preload assembly 480 causes motor pack 446 to movepredetermined distance Zload plus an additional distance A so that motorpack 446 is at position 434. The movement of motor pack 446 theadditional distance A compresses the preload spring assembly in eachdrive output assembly 443 of the plurality of drive output assemblies sothat a second preload force is exerted on each drive output disk 545 inthe plurality of drive output disks. The second preload force reducesany backlash between rotation of the motor shaft in drive units 441 androtation of shaft 467 in surgical instrument 460 to less than 0.7degrees before the distal end of surgical instrument 260 exits thecannula.

The movement of motor pack 446 the additional distance A also furtherstretches return spring 447, and in addition inserts each of pluralityof hard stops 437 into a corresponding hard stop receptacle in pluralityof hard stop receptacles 457. Plurality of hard stops 437 prevents anyproximal movement of moveable body 451C in surgical device interfaceelement 450. The combination of plurality of hard stops 437 andplurality of hard stop receptacles 457 form a surgical instrumentremoval interlock and prevent removal of surgical instrument 460. If aperson tries to engage the release buttons on surgical instrument 460,the mechanism in surgical instrument 460 cannot push movable body 451Cin surgical device interface element 450 proximally, because pluralityof hard stops 437 prevent any proximal movement of moveable body 451C,and so intermediate disk 453 and driven disk 464 cannot be disengaged.

The use of plurality of hard stop receptacles 457 is illustrative onlyand is not intended to be limiting. In another aspect, plurality of hardstop receptacles 457 is not used. Instead, plurality of hard stops 437contact a proximal surface of moveable body 451C and prevent movement ofmoveable body 451C in the proximal direction.

If for some reason it is necessary to remove surgical instrument 460while the distal tip of surgical instrument 460 extends beyond thedistal end of the cannula, a person pushes preload release button 482.When pushed, preload release button 482 causes the longitudinal force onmotor pack 446 to be released. Consequently, return spring 447 pullsmotor pack 446 to fully withdrawn position 432.

With motor pack 446 fully withdrawn, plurality of hard stops 437 areretracted from plurality of hard stop receptacles 457 in movable body451C of surgical device interface element 450 and disks 453 and 464 areno longer subject to any preload forces. Thus, the release buttons onsurgical instrument 460 can be used to remove surgical instrument 460from surgical device interface element 450 at any position of insertionassembly 431. In addition, release latch inhibit stop 438 is withdrawn,and release latch 435 can be used to disengage surgical device interfaceelement 450 from instrument manipulator assembly 440 at any position ofinsertion assembly 431. In one aspect, the release of surgical deviceinterface element 450 is inhibited until after preload release button482 is pressed, e.g., release latch inhibit stop 438 inhibits theoperation of release latch 435 until after preload release button 482 ispressed. The preload is automatically reset, as described above, thenext time surgical device interface element 450 is installed andinsertion assembly 431 is moved to the fully retracted position.

FIGS. 5 to 13 illustrate one aspect of installing the parts of surgicaldevice assembly 300 to obtain the configuration illustrated in FIGS. 3Aand 3B. FIG. 5 illustrates the distal end of instrument manipulatorassembly 240. Instrument manipulator assembly 240 includes a drive unitassembly 541 and a drive output unit 542. In this aspect, drive outputunit 542 includes a plurality of drive output assemblies 543P, e.g.,eight drive output assemblies. Herein, drive output assembly 543 refersto any one of the eight drive output assemblies. In one aspect, only sixof the eight drive output assemblies are used. Drive output assembly 543includes a low backlash coupler 544, sometimes referred to as coupler544, and a drive output disk 545. See also FIG. 16A. In one aspect, acoupler that has a backlash of less than 0.3 degrees is considered a lowbacklash coupler.

Drive output disk 545 is coupled to low backlash coupler 544 by a set ofoutput pins. As explained more completely below, drive output disk 545is a cylindrical disk that includes a distal end surface. The distal endof each drive output disk 545 has a drive interface 557. Drive interface557 includes drive dogs and alignment elements. In FIG. 5, the drivedogs and first and second alignment elements extend in the distaldirection from the distal end surface (see FIG. 16C) of drive outputdisk 545.

FIG. 6 shows instrument manipulator assembly 240 affixed to insertionassembly 331 that in turn is attached to an insertion axis base assembly632. Insertion axis base assembly 632 includes a motor and powerelectronics to move insertion assembly 331.

Sterile adapter assembly 250 includes a sterile adapter frame 651 and asterile drape (not shown). The sterile drape is fixedly attached tosterile adapter frame 651. Sterile adapter assembly 250 is an example ofa surgical device interface element. Sterile adapter frame 651 is anexample of a surgical device interface element body. In more generalterms, a surgical device interface element is a structure that includesa mechanical interface between a drive interface of a drive system and adriven interface of a surgical instrument.

A plurality of tongues 652A, 652B extends from a first end 651A ofsterile adapter frame 651. First end 651A is sometimes referred to as aclosed end of sterile adapter assembly 250 and of sterile adapter frame651. Each tongue 652A, 652B is configured to mate with a correspondinggroove 647A, 647B in a plurality of grooves in drive output unit 542. Asecond end 651B of sterile adapter frame 651 includes a lip 654 that isengaged by a sterile adapter release latch 635 of drive output unit 542when sterile adapter frame 651 is mounted on drive output unit 542.Second end 651B is sometimes referred to as an open end of sterileadapter assembly 250 and of sterile adapter frame 651.

As explained more completely below, sterile adapter frame 651 includes amovable body 651C. Moveable body 651C can move in the proximal anddistal directions within sterile adapter frame 651.

A plurality of intermediate disks 653P is mounted in a plurality ofintermediate disk receptacles of movable body 651C so that eachintermediate disk can rotate relative to sterile adapter frame 651 andrelative to movable body 651C. Thus, plurality of intermediate disks653P is rotatably mounted in sterile adapter frame 651. Intermediatedisk 653 is representative of each intermediate disk in plurality ofintermediate disks 653P. Intermediate disk 653 is a representativeintermediate disk.

Each intermediate disk 653 includes an intermediate driven interface 655on a first side of intermediate disk 653 and an intermediate driveinterface 756 (FIG. 7) on a second side of intermediate disk 653. Thefirst side is opposite and removed from the second side. Intermediatedriven interface 655 of each intermediate disk 653 is visible in FIG. 6with intermediate disk 653 mounted in an intermediate disk receptacle ofmovable body 651C. Intermediate driven interface 655 is configured tomate with a drive interface 557 on drive output disk 545 in drive outputunit 542.

To mount sterile adapter assembly 250 on instrument manipulator assembly240, each tongue 652A, 652B is inserted into a corresponding groove647A, 647B in drive output unit 542. See FIG. 7A. Sterile adapter frame651 is then rotated until lip 654 is engaged by sterile adapter releaselatch 635. Referring to elements 652A, 652B as tongues and referring toelements 647A, 647B as grooves is illustrative only and is not intendedto be limiting. Alternatively, elements 652A, 652B could be described astenons or projections, and elements 674A, 647B could be described asmortises or cavities.

When sterile adapter frame 651 is latched to drive output unit 542, asillustrated in FIG. 7B, plunger 546 of instrument manipulator assembly240 is depressed. When plunger 546 is depressed, a signal is generatedthat indicates to controller 290 the presence of sterile adapterassembly 250. In response to the signal, controller 290 in surgicalsystem 200 first energizes an automatic preload reset mechanism (seeFIG. 24B) that generates a preload force on each drive output disk 545of plurality of drive output disks 545P (FIG. 5), and then controllersends a signal to instrument manipulator assembly 240 to rotate eachdrive output disk 545 of plurality of drive output disks 545P.

As explained more completely below, each drive output assembly 543 indrive output unit 542 is spring-loaded and is automatically positionedso that a preload force is exerted on each drive output disk 545 aftersterile adapter assembly 250 is mounted on instrument manipulatorassembly 240. The preload force pushes against drive output disk 545 andagainst a corresponding intermediate driven interface 655 ofintermediate disk 653 in sterile adapter frame 651.

However, in FIG. 7B, when sterile adapter frame 651 is first mounted oninstrument manipulator assembly 240, the elements of the intermediatedriven interface 655 may not be aligned with corresponding elements ofdrive interface 557 on drive output disk 545. If the elements of the twodisks 653 and 545 are not aligned, the two disks are partially coupled,but the two disks are not mated to each other. Thus, a disk stackincluding disks 545 and 653, i.e., a first disk and a second disk, whichare partially coupled has a first height. After the preload force isapplied to this disk stack, the controller rotates drive output disk545.

As explained more completely below, rotation of intermediate disk 653 isinhibited while drive output disk 545 is rotated until the two disks aremated. Also, as explained more completely below, the coupling of theelements of drive interface 557 on drive output disk 545 with thecorresponding elements of intermediate driven interface 655 onintermediate disk 653 assure that the two disks remain partially coupledunder the preload force while drive output disk 545 is rotated. When thetwo disks are mated, in one aspect, the height of the disk stack has asecond height, and the second height is less than the first height, asensor in instrument manipulator assembly 240 detects this change inheight and sends a signal to controller 290 to stop the rotation ofdrive output disk 545. An alternative way to detect the mating of thedrive output disk and the intermediate disk is described below.

FIG. 7B also shows a preload assembly 780 that is coupled to a motorpack in drive unit assembly 541. Preload assembly 780 is a more detailedexample of one aspect of preload assembly 480.

Preload assembly 780 rides on a preload track (see preload track 2225 inFIG. 22A) in insertion assembly 331. Instrument manipulator assemblyhousing 741 and instrument sterile adapter assembly 250 are fixedlyattached to a distal end of insertion assembly 331 and move as a unitwith the distal end of insertion assembly 331.

However, a motor pack (see FIGS. 22A to 22B) within instrumentmanipulator assembly housing 741 can move in the distal and proximaldirections relative to instrument manipulator assembly housing 741. Asexplained more completely, as preload assembly 780 moves in the distaldirection, preload assembly 780 provides a longitudinal force in thedistal direction on the motor pack. The longitudinal force results incompression of springs in drive output assembly 543 that generates asecond preload force. The second preload force reduces any backlash toless than 0.7 degrees before the distal end of surgical instrument 260exits the cannula.

Returning to FIG. 7A, an intermediate drive interface 756 on the distalside of intermediate disk 653 of plurality of intermediate disks 653P isvisible. Also visible in FIGS. 7A and 7B is an instrument insertion skidplate 755B, which extends from an inner side surface of sterile adapterframe 651. There is a similar instrument insertion skid plate 755A thatextends from an inner side surface on the opposite side of sterileadapter frame 651. In FIGS. 7A and 7B, a side 751B, sometimes called lip751B of movable body 651C is also visible. Side 751A is shown in FIG.11.

FIGS. 8A to 8I illustrate an alternative example, sterile adapterassembly 250A, of surgical device interface element 450 and of sterileadapter assembly 250. Sterile adapter assembly 250A includes a sterileadapter frame 851 and a sterile drape (not shown). The sterile drape isfixedly attached to sterile adapter frame 851. Sterile adapter frame 851is an example of a surgical device interface element body.

A plurality of grooves 852A, 852B (FIGS. 8H and 8I) extend into a firstend 851A of sterile adapter frame 851 to form first and second lips852A1, 852B1. First end 851A is sometimes referred to as a closed end ofsterile adapter assembly 250A and of sterile adapter frame 851. Thedepth and size of each groove 852A, 852B is configured to allow asurface of a corresponding hook 847A, 847B on a distal end of ventrallatch assembly 847 to engage a corresponding lip 852A1, 852B1.

Each of first and second lips 852A1, 852B1 includes a first surface anda second surface. The second surface is opposite the first surface,e.g., the first surface is a proximal surface and the second surface isa distal surface. The second surface of the lip is longer than the firstsurface of the lip in a direction perpendicular to axis 890. A thirdsurface of the lip extends between the first and second surfaces, and istapered in view of the different lengths of the first and secondsurfaces. In one aspect, the third surface is a beveled surface.

A second end 851B of sterile adapter frame 851 includes a lip 854 thatis engaged by a lip 835L that extends inward towards axis 890 from adistal portion of a sterile adapter release latch 835 of drive outputunit 542A when sterile adapter assembly 250A is mounted on drive outputunit 542A. Second end 851B is sometimes referred to as an open end ofsterile adapter assembly 250A and of sterile adapter frame 851.

Lip 854 includes a first surface and a second surface. The secondsurface is opposite the first surface, e.g., the first surface is aproximal surface and the second surface is a distal surface. The secondsurface of lip 854 is longer than the first surface of lip 854 in adirection perpendicular to axis 890. A third surface of lip 854 extendsbetween the first and second surfaces, and is tapered in view of thedifferent lengths of the first and second surfaces. In one aspect, thethird surface is a beveled surface.

As explained more completely below, sterile adapter frame 851 includes amovable body 851C. Moveable body 851C can move in the proximal anddistal directions within sterile adapter frame 851. An instrumentinsertion skid plate 855A extends from an inner side surface of sterileadapter frame 851. There is a similar instrument insertion skid plate855B that extends from an inner side surface on the opposite side ofsterile adapter frame 851. In FIGS. 8A, a side 851C1, sometimes called alip 851C1 of movable body 851C is also visible.

The features and operation of movable body 851C are the same as thefeatures and operation of movable body 651C, and so the description ofthe features and operation of moveable body 651C are not repeated herefor movable body 851C. Also, the mounting of a surgical instrument onsterile adapter assembly 250A is the same as described with respect tosterile adapter assembly 250, and so that description is not repeatedfor sterile adapter assembly 250A.

To mount sterile adapter assembly 250A on instrument manipulatorassembly 240, sterile adapter assembly 250A is moved axially in theproximal direction along longitudinal axis 890, i.e., the directionindicated by arrow 891 (FIGS. 8A and 8B) until sterile adapter assemblyis engaged by features of drive output unit 542A, as described morecompletely below. FIGS. 8B to 8D are cut-away drawings that illustratethe elements using in mounting sterile adapter assembly 250A to driveoutput unit 542A. Drive output unit 542A is similar to drive output unit542 with the exception of latching mechanism 860 for sterile adapterassembly 250A that is included in drive output unit 542A.

A frame 842F of drive output unit 542A includes a first sterile adapteralignment element 845A, sometimes referred to as a first alignmentelement, extending from the distal face of frame 842F and a secondsterile adapter alignment element 845B, sometimes referred to as asecond alignment element also extending from the distal face of frame842F. Sterile adapter alignment element 845A is adjacent but inboard ofventral latch assembly 847, while sterile adapter alignment element 845Bis adjacent but inboard of sterile adapter release latch 835.

As sterile adapter assembly 250A moves axially to the proximity of thedistal face of drive output unit 542A, first sterile adapter alignmentelement 845A enters, e.g., engages, first sterile adapter alignmentreceptacle 853A (FIGS. 8H and 8I) in sterile adapter frame 851.Similarly, second sterile adapter alignment element 845B enters, e.g.,engages, second sterile adapter alignment receptacle 853B in sterileadapter frame 851. The alignment elements and receptacles are configuredto align sterile adapter assembly 250A so that further motion of sterileadapter assembly 250A in the proximal direction causes latchingmechanism 860 to engage sterile adapter assembly 250A.

First and second alignment elements 845A, 845B are an example of aplurality of sterile adapter alignment elements. First and secondalignment receptacles 853A, 853B are an example of a plurality ofalignments receptacles. Thus, drive output unit 542A, and so instrumentmanipulator assembly 240, in this aspect, includes a plurality ofsterile adapter alignment elements, and sterile adapter assembly 250Aincludes a plurality of alignment receptacles. Alternatively, theplurality of receptacles could be formed in drive output unit 542A, andthe plurality of alignment elements could extend from the proximal faceof sterile adapter frame 851.

As sterile adapter assembly 250A moves further in the proximaldirection, a tapered surface of hook 847A contacts the tapered surfaceof lip 852A1 of sterile adapter assembly 250A, and a tapered surface ofa tapered surface of hook 847B contacts the tapered surface of lip 852B1of sterile adapter assembly 250A. Similarly, a tapered surface of lip835L of sterile adapter release latch 835 contacts the tapered surfaceof lip 854 of sterile adapter assembly 250A.

Further motion of the sterile adapter assembly 250A in the proximaldirection causes a distal end portion of sterile adapter release latch835 to pivot outward away from axis 890 of drive output unit 542A, andhooks 847A, 847B of ventral latch assembly 847 to pivot outward, awayfrom axis 890 of drive output unit 542A. After hooks 847A and 847B andlip 835L move distally beyond lips 852A1 and 852B1, and after lip 835Lmoves distally beyond lip 854, hooks 847A and 847B and lip 835L pivotinward towards axis 890 so that lip 835L engages lip 854, hook 847Aengages lip 852A1, and hook 847B engages lip 852B1. Specifically, aproximal surface of each hook contacts the second surface of thecorresponding lip. Hence, sterile adapter assembly 250A is mounted ondrive output unit 542A, as illustrated in FIG. 8D, by only movingsterile adapter assembly 250 along axis 890 toward the distal face ofdrive output unit 542A.

FIGS. 8E to 8G are cut-away drawings illustrating sterile adapterlatching mechanism 860. Components that are not needed to understandsterile adapter latching mechanism 860 are not included in FIGS. 8E to8G. Sterile adapter latching mechanism 860 is movably coupled to frame842F of drive output unit 542A. Sterile adapter latching mechanism 860includes sterile adapter release latch 835, push rod 844, and ventrallatch assembly 847. Push rod 844 couples sterile adapter release latch835 to ventral latch assembly 847 so that motion of latch 835 istransferred to ventral latch assembly 847. Thus, the sterile adapterlatching mechanism includes a first latch assembly, a second latchassembly, and a push rod coupling the first latch assembly to the secondlatch assembly.

Sterile adapter release latch 835, sometimes referred to as latch 835,includes a proximal end portion—an example of a first end portion—and adistal end portion—an example of a second end portion opposite from thefirst end portion. A latch pin 835P (FIG. 8B) is coupled to an interiorsurface of the proximal end portion of latch 835. Latch pin 835P extendsinward from the interior surface of latch 835. Latch pin 835P isequivalent to latch pin 435P and latch pin 2635P, and so the descriptionof those latch pins is directly applicable to latch pin 835P, andconversely. Lip 835L extends inward from the distal portion of latch835. In this aspect, sterile adapter release latch 835 is pivotallyconnected to frame 842F. The pivotal connection is spring loaded tomaintain latch 835 in what is referred to as the engaged position, orengaged state in the absence of a force that causes latch 835 to pivot.A first end of push rod 844 is pivotally connected to the proximal endportion of latch 835 so that when the proximal portion of latch 835 ispushed inward, e.g., pushed in a first direction, the motion istransferred to push rod 844.

In this aspect, a proximal end portion, e.g., a first end portion, ofventral latch assembly 847 is pivotally connected to frame 842F. In oneaspect, the connection to frame 842F is spring-loaded to maintainventral latch assembly 847 in what is referred to as the engagedposition, or engaged state in the absence of a force that causes ventrallatch assembly 847 to pivot. Two legs extend distally from the proximalend portion of ventral latch assembly 847. At the distal end of eachleg, e.g., at the distal end of ventral latch assembly 847, is a hook,i.e., one of hook 847A and hook 847B. Push rod 844 is pivotly connectedto one leg of ventral latch assembly 847 between the proximal endportion of latch assembly 847 and the distal end of the leg.

In this aspect, ventral latch assembly 847 is implemented as a Class 3lever, the effort is between the fulcrum (pivotal connection to frame)and the load (hooks 847A and 847B). Use of a Class 3 lever isillustrative only and is not intended to be limiting. In other aspects,a Class 1 lever or a Class 2 lever could be used. For a Class 2 lever,the load is between the fulcrum and the effort, and for a Class 1 lever,the fulcrum is between the effort and the load.

As shown in FIG. 8F, in a first state where no external forces areacting on sterile adapter release latch 835, both sterile adapterrelease latch 835 and ventral latch assembly 847 are in a steady-stateposition, the engaged position, with a longitudinal axis of each alignedwith longitudinal axis 890, i.e., substantially parallel to axis 890.Here, substantially parallel means parallel within manufacturingtolerances. In a second state, where an external force 892 is applied tothe proximal end of latch 835 (FIG. 8G), or alternatively, a force isapplied to lip 835L, the proximal end portion of latch 835 pivots inwardtoward axis 890 and the distal end portion of latch 835 pivots outward.In response to the motion of latch 835, the distal end portions ofventral latch assembly 847 pivot outward. Thus, external force 892causes the two latch assemblies to move to the disengaged position,e.g., move to a second state different from the first state.

FIG. 8H is bottom perspective view of sterile adapter assembly 250A.FIG. 8I is a top perspective view of sterile adapter assembly 250A.While it is not shown in FIGS. 8H and 8I, an intermediate disk 653 ismounted in each of the plurality of intermediate disk receptacles inmovable body 851C. As for sterile adapter assembly 250 (FIG. 6), aplurality of intermediate disks is mounted in the plurality ofintermediate disks receptacles of movable body 851C so that eachintermediate disk can rotate relative to sterile adapter frame 851 andto movable body 851C. Thus, a plurality of intermediate disks isrotatably mounted in sterile adapter frame 851. The plurality ofintermediate disks is the same as plurality of intermediate disks 653P,and so the characteristics of the plurality of intermediate disks arenot repeated here. Also, each intermediate disk in the plurality ofdisks mounted in movable body 851C is the same as intermediate disk 653(see FIG. 17B), and so the description of intermediate disk 653 is notrepeated with respect to sterile adapter assembly 250A.

The plurality of hard stop receptacles 857 of sterile adapter assembly250A is the same as and works in the same way as described for pluralityof hard stop receptacles 1757, and so that description is not repeatedhere. Sterile adapter assembly 250A has an intermediate disk hard stop861 associated with each intermediate disk. Each intermediate disk hardstop 861 of sterile adapter assembly 250A is the same as and works inthe same way as described for intermediate disk hard stop 1761 (FIG.17B), and so that description is not repeated here

FIG. 9A is a more detailed illustration of surgical instrument 260 inone aspect. Surgical instrument 260, in this aspect, includes a driveninterface assembly 961, a transmission unit 965, a main tube 967, aparallel motion mechanism 968, a wrist joint 969, and an end effector970. Wrist joint 969 is described, for example, in U.S. PatentApplication No. US 2003/0036748 A1 (filed Jun. 28, 2002 disclosing“Surgical Tool Having Positively Positionable Tendon-ActivatedMulti-Disk Wrist Joint”), which is incorporated herein by reference.Parallel motion mechanism 968 is described, for example, in U.S. Pat.No. 7,942,868 B2 (filed Jun. 13, 2007, disclosing “Surgical InstrumentWith Parallel Motion Mechanism”).

As shown in FIG. 9B, driven interface assembly 961 includes a pluralityof driven disks 964P. Plurality of driven disks 964P is an example ofdriven interface elements. Driven disk 964 is representative of eachdriven disk of plurality of driven disks 964P. Driven disk 964 ismounted on a shaft of transmission unit 965. Also, each driven disk 964is mounted in a receptacle in a body of driven interface assembly 961(see FIG. 19B).

Mechanical components (e.g., gears, levers, gimbals, cables etc.) intransmission unit 965 transfer torques from plurality of driven disks964P to cables, wires, and/or cable, wire, and hypotube combinationsthat run through main tube 967 to control movement of parallel motionmechanism 968, wrist joint 969, and end effector 970. Main tube 967,although substantially rigid, can be bent slightly between transmissionunit 965 and entry guide 270. This bending allows the instrument bodytube bores in entry guide 270 to be spaced closer together than the sizeof the transmission units would otherwise allow. The bending isresilient so that main tube 967 assumes its straight shape when surgicalinstrument 260 is withdrawn from entry guide 270 (the main tube may beformed with a permanent bend, which would prevent instrument body roll).

Driven interface assembly 961 has on each side a pair of mounting wings(962A1, 962B1) and (962A2, 962B2). Also, on each side of transmissionunit 965 is a release button 963A, 963B. Mounting wing 962B2 and releasebutton 963B are shown in FIG. 10.

To mount surgical instrument 260 in sterile adapter frame 651, first,mounting wings 962A1, 962A2 are placed on skid plates 755A, 755B (FIGS.10 and 11) at the open end of sterile adapter frame 651. FIG. 11 is acutaway view of FIG. 10 with the outer side surface of sterile adapterframe 651 removed.

Mounting wing 962A1 is resting on skid plate 755A that extends from afirst sidewall of sterile adapter frame 651. As surgical instrument 260is slid on skid plate 755A towards parking slot 1155A, which is at theopposite end of skid plate 755A, (FIG. 11), the top surface of firstmounting wings 962A1, 962A2 contacts the bottom edge of lip 751A, 751B,which moves movable body 651C in the proximal direction (FIG. 12). Theproximal motion of movable body 651C depresses plunger 1246 ofinstrument manipulator assembly 240 in the proximal direction, which inturn generates a signal to controller 290 that surgical instrument 260is being loaded unto sterile adapter assembly 250.

When mounting wing 962A1 reaches parking slot 1155A at the closed end ofsterile adapter frame 651 (FIG. 13), the top surface of first mountingwings 962A1, 962A2 no longer contacts the bottom edge of lip 751A, 751B.Consequently, the preload force on movable body 651C moves body 651C inthe distal direction (FIG. 13) and locks first mounting wing 962A1 inplace. When first mounting wing 962A1 reaches the closed end of sterileadapter frame 651, second mounting wing 962B1 rests on a flat portion ofskid plate 755A near the open end of sterile adapter frame 651.

Each intermediate disk 653 in sterile adapter frame 651 is being pushedaxially in the distal direction by the preload force on the plurality ofdrive output disks 545P. Thus, as surgical instrument 260 is mounted insterile adapter frame 651, plurality of intermediate disks 653P transferthe first preload force to movable body 651C so that the preload forceis applied to mounting wing 962A1. This preload force is selected sothat surgical instrument 260 can be easily slid into sterile adapterframe 651 and so that a small preload force is maintained on all thedisks.

When surgical instrument 260 is mounted in sterile adapter assembly 250,instrument manipulator assembly 240 detects the presence of surgicalinstrument 260 and sends a signal to controller 290 that indicates thepresence of surgical instrument 260. In response to the signal,controller 290 in surgical system 200 sends the signal to instrumentmanipulator assembly 240 to rotate each drive output disk 545 ofplurality of drive output disks 545P.

As explained more completely below, each drive output assembly 543 indrive output unit 542 is spring-loaded and is automatically positionedso that a preload force is exerted on each drive output disk 545 aftersterile adapter assembly 250 is mounted on instrument manipulatorassembly 240. The preload force pushes against drive output disk 545 andagainst a corresponding intermediate driven interface 655 ofintermediate disk 653 in sterile adapter frame 651.

However, in FIG. 7B, when surgical instrument 260 is first mounted onsterile adapter assembly 250, the elements of the intermediate driveinterface 765 of intermediate disk 653 may not be aligned withcorresponding elements of driven interface 980 on driven disk 964. Ifthe elements of the two disks 653 and 964 are not aligned, the two disksare partially coupled, but the two disks are not mated to each other.Thus, a disk stack including disks 964, 653, and 545, i.e., a thirddisk, the second disk, and the first disk, which are partially coupledhas a third height.

When surgical instrument 260 is mounted in sterile adapter frame 651,each driven disk 964 in driven interface assembly 961 pushes acorresponding intermediate disk 653 in sterile adapter assembly 250proximally so that intermediate disk 653 can rotate freely. As explainedmore completely below, when intermediate drive interface 756 of anintermediate disk 653 in sterile adapter assembly 250 is not alignedwith corresponding driven interface 980 of a driven disk 964 in driveninterface assembly 961, an engagement structure on intermediate driveinterface 756 of intermediate disk 653 engages a rotation disableelement 1980 (see FIG. 19A) on driven disk 964 of surgical instrument260, which prevents rotation of driven disk 964 in driven interfaceassembly 961.

As intermediate drive interface 756 of intermediate disk 653 rotateswith driven disk 964 fixed in place, each element on intermediate driveinterface 756 rotates into alignment with the corresponding element ofdriven interface 980 of driven disk 964 and mates with the correspondingelement. The coupling of intermediate drive interface 756 and driveninterface 980 releases the rotation lock on driven disk 964. Thus, thestack of disks rotates as a unit. When all three disks are mated, theheight of the disk stack has a fourth height, and the fourth height isless than the third height, a sensor in instrument manipulator assembly240 detects this change in height and sends a signal to controller tostop the rotation of drive output disk 545. The sensor in instrumentmanipulator assembly 240 that detects changes in the height of the diskstack can be a mechanical sensor, an optical sensor, an inductivesensor, a capacitive sensor, etc.

FIG. 14 is an illustration of disk stack 1400 when drive output disk 545is coupled to intermediate disk 653, and intermediate disk 653 iscoupled to driven disk 964. Herein, coupled means that all of thealignment features on two interfacing disks are aligned so that the twodisks are mated, i.e., fully coupled. As described above, when some ofthe alignment features on two interfacing disks are aligned, but otheralignment features on the two interfacing disks are not aligned, the twointerfacing disks are partially coupled. The preload force is selectedso that despite some backlash, the two partially coupled disks remain incontact so that all the alignment features can be aligned and mated.

Disk stack 1400 is the disk stack configuration referred to above withrespect to FIGS. 3A and 3B. Drive interface 557 of drive output disk 545is mated to intermediate driven interface 655 of intermediate disk 653and intermediate drive interface 756 of intermediate disk 653 is matedto driven interface 980 of driven disk 964. As explained more completelybelow, when there is a high preload force, i.e., a second preload force,on the stack of disks 1400, there is zero backlash between the disks indisk stack 1400 for torque levels used in surgical procedures eventhough shaft 1466 may not be precisely aligned with the shaft coupled todrive output disk 545. When disks 545, 653, and 964 in stack of disks1400 are mated under the second preload force, there is zero backlash inthe couplings between the disks for torque levels used in surgicalprocedures. Low backlash coupler 544 compensates for spatialmisalignment and transmits motion and torque to disk stack 1400. Asexplained more completely below, the design of drive dogs compensatesfor angular misalignment of the drive output disk 445 and the drivendisk 964.

FIG. 15A is an illustration of instrument manipulator assembly 240 withinstrument manipulator assembly housing 741 removed. Also, there is avertical cut showing the components in drive unit assembly 541.Instrument manipulator assembly 240 includes a motor pack 1541 that inturn includes a plurality of drive units 1500P and plurality of driveoutput assemblies 543P. Each drive unit 1500 of plurality of drive units1500P includes an encoder 1501, a slotless brushless servomotor 1502, acompact Hall effects sensor 1503, and a planetary gearhead 1504.

In one aspect, slotless brushless servomotor 1502 has a very high motorconstant, and so servomotor 1502 is very efficient. The use of aslotless brushless servomotor is illustrative only and is not intendedto limit the motors in plurality of drive units 1500P to this specifictype of motor. A variety of motors can be used including brush typemotors, stepper motors, etc. Each servomotor 1502 includes magneticshielding to prevent torque ripple to adjacent servomotors in view ofthe compact configuration of the eight servomotors in motor pack 1541.

Compact Hall effects sensor 1503 is used to detect the position of thepermanent magnet in servomotor 1502. Hall effects sensor 1503 is used asa second encoder. An encoder-to-hall check compares the rotary positionsreported by encoder 1501 and Hall effects sensor 1503. If the rotarypositions are significantly different, something is wrong with encoder1501, Hall effects sensor 1503, or the mechanism between them. Executingsoftware in a controller immediately turns off the motors, when thischeck fails.

Planetary gearhead 1504 is heavy duty and highly efficient (greater than90%), and thus is easier to back-drive than typical gearheads. By backdrivable, it is meant that the output shaft of the gearhead can berotated with a relatively low torque, as compared to typical gearheads.

Planetary gearhead 1504 has backlash, in one aspect, of less than onedegree, and in another aspect has low backlash, e.g., 0.4 degrees. Inone aspect, four of the planetary gearheads have a 28:1 input to outputratio and are referred to as standard planetary gearheads. In thisaspect, four of the planetary gearheads have a 9 to 1 input to outputratio and are referred to as high-speed gearheads. Similarly a driveunit 1500 with a standard planetary gearhead is referred to as astandard drive unit. A drive unit 1500 with a high-speed planetarygearhead is referred to as a high-speed drive.

FIGS. 15B to 15E are illustrations of one example of planetary gearheadssuitable for use in motor pack 1541. FIG. 15B is a side view ofplanetary gearhead 1504. FIG. 15C is a distal view of planetary gearhead1504. FIG. 15D is a proximal view of a 28:1 planetary gearhead. FIG. 15Eis a proximal view of a 9:1 planetary gearhead. One example ofdimensions for the gearhead in FIGS. 15B to 15E is given in Table 1.

TABLE 1 REFERENCE NUMBER DIMENSION L1 1.043 inches L2 1.070 inches L30.673 inches L4 0.698 ± 0.002 inches L5 0.738 inches L6 0.030 inches D10.684 inches (diameter) A1 5.00 degrees D2 0.750 inches (diameter) D30.699, 0.700 inches (diameter) W1 0.698, 0.700 inches W2 0.385 ± 0.003inches A2 45.00 degrees R1 0.32 inches radius thru flange align tooctagon ± 3 degrees

FIGS. 16A to 16D are more detailed illustrations of drive outputassembly 543 that is representative of each drive output assembly inplurality of drive output assemblies 543P in this aspect. Drive outputassembly 543 includes a ball-spline 1603. A light preload spring 1601,e.g., a first preload spring, is mounted in a central lumen ofball-spline 1603, and has one end affixed to a proximal side of driveoutput disk 545. Light preload spring 1601 applies a first preload forceto drive output disk 545 when spring 1601 is compressed. In one aspect,the first preload force is 0.5 pounds force (Lbf).

A ball-spline nut 1604 is mounted is mounted on ball-spline 1603.Ball-spline nut 1604 slides proximally and distally along ball-spline1603, i.e., slides in a first direction and in a second directionopposite to the first direction, while transferring torque/motion fromball-spline 1603. Thus, torque/motion is transferred to low backlashcoupler 544, sometimes called flexure 544, through ball-spline 1603.Ball-spline 1603 transmits torque/motion, while allowing drive outputassembly 543 to move along a longitudinal axis of ball-spline 1603. Asdisks are engaged or disengaged in disk stack 1400, drive outputassembly 543 moves in and out along ball-spline 1603 to facilitate theengagement or disengagement. Ball-spline 1603 has zero backlash fortorque levels used in surgical procedures.

Ball-spline nut 1604 is inserted in a housing 1605 on which heavypreload spring 1602, a second preload spring, is mounted. Heavy preloadspring 1602 in combination with light preload spring 1601 applies asecond preload force to drive output disk 545, when both springs arecompressed. In one aspect, the second preload force is 2.3 pounds force(Lbf)

Flexure 544 is coupled to the drive unit by two pins that transmittorque from the drive unit to flexure 544. Flexure 544 is also coupledto drive output disk 545 by two pins. Thus, flexure 544 transfers torquefrom the drive unit to drive output disk 545. FIG. 16B is an end view offlexure 544.

Flexure 544 has a central lumen 1640 that fits on a cylinder 1445C(FIGS. 14 and 16A) extending proximally from a proximal surface of driveoutput disk 545. Flexure has four beams 1641A, 1641B, 1641C, and 1641D.A first end of each of four beams 1641A, 1641B, 1641C, and 1641D isconnected to a body 1642 of flexure 544. A second end of each of fourbeams 1641A, 1641B, 1641C, and 1641D is connected to a cylinder 1643A,1643B, 1643C, and 1643D, respectively, having a central bore. Beams1641A, 1641B, 1641C, and 1641D are stiff in torsion about the axisthrough central lumen 1640, but flexible with respect to lateraloffsets.

Output pins driven by the drive unit are mounted in the central bores ofcylinders 1643A, 1643B. Input pins of drive output disk 545 are mountedin central bores of cylinders 1643C, 1643D.

Flexure 544 is a precision-machined one-piece part made ofprecipitation-hardened stainless steel 17-4 H1150, in one aspect. Thebacklash of flexure 544 is determined by the mounting pin clearancesbetween the central bore of the cylinder and the outer diameter of theinput pin or the output pin. The backlash of surgical device assembly300 is controlled solely by instrument manipulator assembly 240, in thisaspect. This is in contrast to previous systems where the backlash wasaccounted for by an Oldham coupling in the prior art sterile adapter.The parts in the prior art sterile adapter were injection molded and socould not be made to the same precision as flexure 544. Controllingbacklash in a reusable part of surgical device assembly 300, e.g.,instrument manipulator assembly 240, means that the backlash isconsistent for each use of surgical device assembly 300 and is notdependent on the manufacturing tolerances of injection molded parts in asingle-use disposable assembly, such as the prior art sterile adapter.

Flexure 544 accommodates motion in two-degrees of freedom in the planenormal to the axis of central lumen 1640. Output pins coupled to beams1641A, 1641B can move along axis 1690. The range of motion is limited bythe gap between the outer surface of cylinder 1643A, 1643B and the outersurface of body 1642. Similarly, input pins coupled to beams 1641C,1641D can move along axis 1691, which is perpendicular to axis 1690. Therange of motion is limited by the gap between the outer surface of thecylinder 1643C, 1643D and the outer surface of body 1642. In one aspect,to displace a beam 0.010 inches along one of axes 1690, 1691 takes 0.66Lbf and results in 29,000 pounds per square inch stress. At 100 in-Lbfapplied torque, the peak stress was 38,000 pounds per square inch.

The two degrees of freedom of flexure 544 accommodate shaftmisalignment. Specifically, drive unit assembly 541 can toleratemisalignment of drive shafts in motor pack 1541 with shafts intransmission unit 965, because each flexure 544 transfers torque todrive output disk 545 while flexing to compensate for a shaft 1466 (FIG.14) that is not perfectly co-axial with the corresponding drive shaft ofdrive unit 1500.

FIG. 16C is a more detailed illustration of one aspect of a driveinterface 557 of drive output disk 545, e.g., the distal part of driveoutput disk 545. Drive output disk 545 has a cylindrical body. FIG. 16Dis a cross-sectional view of drive output disk 545 with drive dog 1652A.

Two bores 1651A, 1651B extend through drive output disk 545. An inputpin is fitted in each bore 1651A, 1651B and into a corresponding bore incylinders 1643A, 1643B of flexure 544.

Two drive dogs 1652A, 1652B, a first alignment element—center post 1653and tab 1654—and a second alignment element, pin 1655, extend distallyfrom a distal end surface 1656 of drive output disk 545. Center post1653 has a height that is larger than a height of tab 1654 and so helpsto center drive output disk 545 with respect to a correspondingalignment receptacle in intermediate driven interface 655 ofintermediate disk 653. Tab 1654 extends from center post 1653 towards acircumferential edge of distal end surface 1656. Centerlines 1670 and1671 extend through and intersect at the center of center post 1653.Center post 1653 and tab 1654 assist in aligning drive output disk 545to intermediate disk 653. Center post 1653 and tab 1654 also providestability to the mated pair of disks.

Pin 1655, in this aspect, is also centered on centerline 1670 and ispositioned between center post 1653 and an edge of distal end surface1656. Pin 1655 is a segment of a cylinder, e.g., the cylinder has beencut vertically by a plane to so that a portion of the outer surface ofpin 1655 is flat and not cylindrical. In one aspect, pin 1655 has agenerally three-dimensional D-shape. Here, a generally three-dimensionalD-shape means that the shape is similar enough to a three-dimensionalD-shape to be recognized as a three-dimensional D shape, e.g., the shapeof pin 1655. Pin 1655 is configured to mate with an alignment receptaclein intermediate disk 653.

The shape and orientation of the first and second alignment elements isillustrative only and is not intended to be limiting. Other shapes ofthe alignment elements and other orientations between the alignmentelements may be used so long as backlash is not introduced under thesecond preload force, the elements do not bind when engaging anddisengaging, and the elements provide stability to the mated pair ofdisks.

Drive interface 557 includes two drive dogs 1652A, 1652B. Each of drivedogs 1652A, 1652B extend distally from distal end surface 1656. Each ofdrive dogs 1652A, 1652B is a same radial distance Rdog from alongitudinal axis of drive output disk 545. The longitudinal axis ofdrive output disk 545 runs through the center of center post 1653. Also,each drive dog 1652A, 1652B is close to the circumferential edge ofdistal end surface 1656. The combination of radially equidistant drivedogs 1652A, 1652B and positioning drive dogs 1652A, 1652B adjacent thecircumferential edge allows drive dogs 1652A, 1652B to efficientlytransfer torque/motion to intermediate disk 653.

The location of the drive dogs 1652A, 1652B relative to thecircumferential edge of distal end surface 1656 is determined by thelocation of drive dog receptacles on intermediate disk 653 (see FIG.18A). The diameter of intermediate disk 653 is determined, in part, bythe number of intermediate disks 653 that can fit in movable body 651Cof sterile adapter assembly 250. Drive dogs 1652A, 1652B are sized andpositioned so that drive dogs 1652A, 1652B engage the drive dogreceptacles in intermediate disk 653, as described more completelybelow, and so that drive dogs 1652A, 1652B do not contact the sidewallof movable body 651C.

As illustrated in FIG. 16C, drive dogs 1652A, 1652B have mirror symmetrywith respect to a plane that includes y-axis 1670 and a longitudinalaxis (not shown) of drive output disk 545. The longitudinal axis ofdrive output disk 545 is perpendicular to both axis 1670 and axis 1671at the center of center post 1653.

Each of drive dogs 1652A, 1652B has mirror symmetry with respect to aplane that includes x-axis 1671 and the longitudinal axis of driveoutput disk 545. This plane bisects each of drive dogs 1652A, 1652B.

The size of drive dogs 1652A, 1652B is selected based on strengthrequirements. A length of drive dogs 1652A, 1652B (radially from centerto edge) in this application is determined by size constraints of thealignment features/antirotation features in the center of disk 545, andthe height of drive dogs 1652A, 1652B is minimized to reduce the sizeand weight of the mechanism while assuring proper engagement withintermediate disk 653 under both the first and second preload forces.

Drive dog 1652A is the same as drive dog 1652B and so only thecharacteristics of drive dog 1652A are considered in further detail. Thedescription of drive dog 1652A is directly applicable to drive dog 1652Band so the description is not repeated for drive dog 1652B.

Drive dog 1652A has a first portion 1652A1 and a second portion 1652A2.First portion 1652A1 extends distally from distal end surface 1656 tosecond portion 1652A2. Second portion 1652A2 extends from first portion1652A1 in the distal direction.

First portion 1652A1 of drive dog 1652A is a three-dimensional rectangleand so has four straight sides extending from distal end surface 1656,e.g., sides 1652 s 2, 1652 s 4 in FIG. 16D. Herein, straight meanssubstantially parallel to plane including a longitudinal axis of drivedog 1652A and one of x-axis 1671 and y-axis 1670. The axis chosendepends on the side of the three-dimensional rectangle being considered.Substantially parallel means parallel to within manufacturingtolerances.

Second portion 1652A2 (FIG. 16D) includes two opposing sides 1652 cyl 2,1652 cyl 4 that are curved surface. In one aspect, the curved surface isa portion of a circular section, e.g., a portion of an outer surface ofa cylinder 1658. Side surfaces 1652 cyl 2, 1652 cyl 4 are outer surfacesof a section of cylinder intersected by two parallel planes that includeedges 1652 e 1, 165 e 2 and that extend out of FIG. 16D. Thus, sidesurfaces 1652 cyl 2, 1652 cyl 4 are curved surfaces.

In one aspect, cylinder 1658 has a diameter of 0.125 inches. The axis ofcylinder 1658 extends out of FIG. 16D. In this aspect, the other twosidewalls of second portion 1652A2 are straight sides.

In one aspect, drive output disk 545 is an injection-molded disk. Driveoutput disk 545 can be made from polycarbonate, polyphenlysulfone(PPSU), polyethylenimine (PEI), etc.

FIG. 17A is another illustration of sterile adapter assembly 250. Asterile drape (not shown) is fixedly attached to a rim 1751, e.g., isaffixed by two-sided tape. Sterile drapes are known and so are notdescribed in further detail. See for example, U.S. Patent No. 7,666,191B2 (filed Dec. 20, 2005), U.S. Pat. No. 7,699,855 B2 (filed Mar. 31,2006), U.S. Patent Application Publication No. US 2011/0277775 A1 (filedAug. 12, 2010), and U.S. Patent Application Publication No. US2011/0277776 A1 (filed Aug. 12, 2010), all of which are incorporatedherein by reference. The sterile drape drapes at least a portion ofsystem 200 to maintain a sterile field during a surgical procedure whilesterile adapter assembly 250 also provides efficient and simpleinstrument exchange in conjunction with an accurate mechanical interfacebetween surgical instrument 260 and its associated instrumentmanipulator assembly 240.

As indicated above, movable body 651C is mounted in sterile adapterframe 651 so that movable body 651C can move in the proximal and distaldirections, i.e., can move in a first direction and in a seconddirection opposite to the first direction relative to the sterileadapter frame. In FIG. 17A, movable body 651C in the distal mostposition. Movable body 651C includes a receptacle for each intermediatedisk 653 in plurality of intermediate disks 653P. Moveable body 651Calso includes a plurality of hard stop receptacles 1757. Eachintermediate disk 653 has a cylindrical body.

In one aspect, each of sterile adapter frame 651, movable body 651C, andthe plurality of intermediate disks 653P are made by injection molding.Suitable materials for sterile adapter frame 651, movable body 651C, andplurality of intermediate disks 653P include polycarbonate,polyphenlysulfone (PPSU), polyethylenimine (PEI), etc.

Each intermediate disk 653 is mounted in a corresponding receptacle inmovable body 651C. Each intermediate disk 653 can rotate within thereceptacle and can move distally and proximally in the receptacle. InFIG. 17A, intermediate disk 653 is in the most distal position. FIG. 17Bis an enlarged illustration of a portion of movable body 651C showing anintermediate disk receptacle 1766 and intermediate disk 653.Intermediate disk 653 has a tab 1767 extending from an outer sidesurface of disk 653 and extending from the proximal end surface of disk653 (see FIG. 18A). Intermediate disk 653 is said to be associated withan intermediate disk hard stop 1761. This means that tab 1767 cancontact hard stop 1761 and upon contact, rotation of intermediate disk653 is stopped.

When surgical instrument 260 is mounted on sterile adapter assembly 250,intermediate disk 653 is displaced proximally relative to movable body651C. In this position, the most distal part of tab 1767, the bottom oftab 1767, is above the most proximal part of hard stop 1761, the top ofstop 1761, so that intermediate disk 653 rotates freely and does notcontact hard stop 1761.

FIGS. 18A and 18B are illustrations of intermediate driven interface 655(FIG. 18A) and intermediate drive interface 756 (FIG. 18B) ofintermediate disk 653. Intermediate driven interface 655 (FIG. 18A) ison a proximal end of intermediate disk 653. Intermediate driveninterface 655 includes a first alignment receptacle and a secondalignment receptacle. In this aspect, the first alignment receptacle isthe combination of center post receptacle 1853 and tab receptacle 1854.The second alignment receptacle is pin receptacle 1855.

The combination of center post receptacle 1853 and tab receptacle 1854is configured to mate with the combination of center post 1653 and tab1654 when post 1653 and tab 1654 are aligned with receptacle 1853 andreceptacle 1854, respectively. Similarly, pin receptacle 1855 isconfigured to mate with pin 1655 when the two are aligned. Thus, driveoutput disk 545 can only mate with intermediate disk 653 in oneorientation, when the alignment elements of disk 545 are aligned withthe alignment receptacles of intermediate disk 653.

Intermediate driven interface 655 also includes two drive dogreceptacles 1852A, 1852B. As illustrated in FIG. 18A, drive dogreceptacles 1852A, 1852B have mirror symmetry with respect to a planethat includes y-axis 1870 and a longitudinal axis (not shown) ofintermediate disk 653. The longitudinal axis of intermediate disk 653 isperpendicular to both axis 1870 and axis 1871.

Each of drive dog receptacles 1852A, 1852B has mirror symmetry withrespect to a plane that includes x-axis 1671 and the longitudinal axisof intermediate disk 653. This plane bisects each of drive dogreceptacles 1852A, 1852B.

Each drive dog receptacle has an inner edge surface that is a samedistance Rrcpt from a longitudinal axis of intermediate disk 653.Theinner edge surface forms the third side of the drive dog receptacle, asexplained more completely below. Since drive dog receptacle 1852A is thesame as drive dog receptacle 1852B, only the characteristics of drivedog receptacle 1852A are considered in further detail. The descriptionof drive dog receptacle 1852A is directly applicable to drive dogreceptacle 1852B and so the description is not repeated for drive dogreceptacle 1852B.

Drive dog receptacle 1852A can be bounded by four sides. In one aspect,a first side is not present, and so the first side is said to be open.The use of an open sidewall is illustrative only and is not intended tobe limiting. In some aspects, the first sidewall can be a solidsidewall. Second and fourth sides are walls that are perpendicular tothe first side. The third side is a wall that is perpendicular to thesecond and fourth sides. Thus, in this aspect, drive dog receptacle1852A is bounded by three walls that extend from an outer proximal edgesurface 1856 of intermediate disk 653 distally into intermediate disk653 to a bottom surface 1857 of drive dog receptacle 1852A. The thirdwall that is opposite to the open side is a straight wall extending fromouter proximal edge surface 1856 to bottom surface 1857. The twoopposing walls, second and fourth walls, have two portions, as describedbelow, a straight wall portion, and a sloped wall portion.

FIG. 18C is a cross-sectional view of drive dog receptacle 1852A cutalong a centerline perpendicular to x-axis 1871. Drive dog receptacle1852A is divided into a first portion 1852A1 and a second portion1852A2. First portion 1852A1 extends into intermediate disk 653 fromouter proximal surface 1856 to second portion 1852A2. Second portion1852A2 extends further into intermediate disk 653 from first portion1852A1 to bottom surface 1857 of drive dog receptacle 1852A.

Opposing walls that bound first portion 1852A1 of drive dog receptacle1852A are straight walls 1852 s 2, 1852 s 4. Typically, a height offirst portion 1852A1 is smaller than the height of portion 1652A1 ofdrive dog 1652A so that there is some space between the distal edgesurface of drive output disk 545 and the proximal edge surface ofintermediate disk 653.

Second portion 1852A2 (FIG. 18C) is bounded by two opposing sidewalls1852 w 2, 1852 w 4 that are a portion of an outer side surface of awedge shape, i.e., sides 1852 w 2, 1852 w 4 are a sloped flat surface.Sidewalls 1852 w 2, 1852 w 4 subtend an angle α. Side surfaces 1852 w 1,1852 w 2 are the surface portions of the wedge shape intersected by twoparallel planes, e.g., a plane that includes line 1852 e 1 and a planethat includes bottom surface 1857. Both of these planes extend out ofFIG. 18C.

In one aspect, the portion of the wedge is selected so that when thedistal end of drive dog 1652A is completely inserted in receptacle 1852,the distal end surface of drive dog 1652A does not contacts bottomsurface 1857, and the cylindrical sidewall portions of cylinder 1658contact sloped sidewalls 1852 w 2, 1852 w 4. In one aspect, for a 0.125diameter of cylinder 1658, angle α is 30 degrees, so sidewalls 1852 w 2,1852 w 4 are portions of sides of a 30-degree wedge shape.

When sterile adapter assembly 250 is mounted on instrument manipulatorassembly 240, the orientation of drive interface 557 on drive outputdisk 545 with respect to the orientation of intermediate driveninterface 655 on intermediate disk 653 is not known. However,irrespective of the relative orientation of the two interfaces, thepreload force on drive output disk 545 pushes intermediate disk 653distally so that intermediate disk 653 is positioned at the most distalpotion in receptacle 1766 (FIG. 17B) of moveable body 651C, e.g.,intermediate disk 653 is in a first axial position. As explained morecompletely below, when surgical instrument 260 is mounted in sterileadapter assembly 250, intermediate disk 653 is displaced proximally to asecond axial position.

As described above, after plunger 546 is depressed by attaching sterileadapter assembly 250 to instrument manipulator assembly 240, driveoutput disk 545 is rotated. Since drive output disk 545 and intermediatedisk 653 are in contact and partially coupled, rotation of drive outputdisk 545 rotates intermediate disk 653. Thus, either interfaces 557 and655 align and mate, or tab 1767 on intermediate disk 653 contacts hardstop 1761. When tab 1767 contacts hard stop 1761, rotation ofintermediate disk 653 is stopped. When interfaces 557 and 655 have notmated and rotation of intermediate disk 653 is stopped, drive outputdisk 545 continues to rotate until the two interfaces mate. Hence, theresult is that disks 545 and 653 are coupled and rotation of driveoutput disk 545 is stopped at hard stop 1761. The control system usesthe stopping of rotation of drive output disk 545 to determine theorientation of drive output disk 545. Note that if the two disks matedprior to reaching hard stop 1761, when hard stop 1761 is reachedrotation of the two-mated disks is stopped.

FIG. 18D is a cross sectional view that illustrates drive dog 1652Ainserted in drive dog receptacle 1852A under a light preload force afterdrive interface 557 on drive output disk 545 has partially-coupled withintermediate driven interface 655 on intermediate disk 653. As describedabove, drive dog 1652A has a first portion 1652A1 with straight sides.The straight sides of first portion 1652A1 blend into a second portion1652A2, a cylindrical tip, as described above. Drive dog receptacle1852A also has a first portion 1852A1 with straight internal sidewalls.First portion 1852A1 blends into a second portion 1852A2 with taperedinternal walls also as described above.

Curved surfaces on two sides of the distal portion of drive dog 1652Aand a sloped slide walls on the corresponding two sides on the distalportion of drive dog receptacle 1852A, where the sloped sidewall istangent to the curved side surface, are illustrative only and is notintended to be limiting. Other surfaces on the distal portion of drivedog 1652A and on the corresponding distal wall portions of drive dogreceptacle 1852A could be used so long as under the high preload force,the second preload force, there is zero backlash in the rotationaldirection between drive output disk 545 and intermediate disk 653 fortorque levels used in surgical procedures, and so long as the interfacebetween the two disks compensates for angular misalignment.

Due to the tapered walls of receptacle 1852A and the cylindricalsurfaces on second portion 1652A2 of drive dog 1652A, an appropriateforce is required to hold drive output disk 545 and intermediate disk653 in place so that the two disks function properly when torque/motionis applied by drive output disk 545 while the two disks are partiallycoupled. In the absence of this force, drive output disk 545 andintermediate disk 653 can separate because the applied torque can drivethem apart.

To prevent this separation under the light preload force, both drive dog1652A and drive dog receptacle 1852A have the first portions withstraight walls, as described above. As drive dog 1652A and drive dogreceptacle 1852A start to separate under torque, the straight wallportions come into contact with one another as shown in FIG. 18C. Atthis point, drive dog 1652A and drive dog receptacle 1852A are no longercapable of driving themselves apart, and the motion can continue with aknown or controlled level of backlash and without drive dog 1652Acompletely inserted into and coupled to drive dog receptacle 1852A. Inone aspect, under the light preload force, the known level of backlashis 1.13 degrees. Thus, the partial coupling between drive output disk545 and intermediate disk 653 has a known level of backlash under thelight preload force.

Also, as shown in FIG. 18D, a small amount of misalignment between theshaft driving disk 545 and the shaft that is driven by intermediate disk653 can be tolerated. In addition, angular misalignment can be toleratedin the direction defined by the axis of blending cylinder 1658 which isinto and out of the page in FIG. 18D.

When drive dog 1652A and drive dog receptacle 1852A are mated togetherunder the high preload force, e.g., the second preload force, asdescribed more completely below, there is no backlash in the interfacebetween the two disks. The second preload force is sufficient to keepdrive dog 1652A and drive dog receptacle 1852A from physically backingapart and separating when torque/motion is applied. Thus, this joint cantransmit torque/motion without backlash. Under the second preload force,the coupling between drive output disk 545 and intermediate disk 653 haszero backlash for torque levels used in surgical procedures.

FIG. 18B is a more detailed illustration of intermediate drive interface756 on the distal end of intermediate disk 653. Intermediate driveinterface 756 includes drive dogs 1862A, 1862B, and an engagementstructure 1863C.

Each of drive dogs 1862A and 1862B is a structure that is equivalent toeach of drive dogs 1652A and 1652B. Specifically, each of drive dogs1862A, 1862B extend distally from distal end surface 1866. An inner edgeof each of drive dogs 1862A, 1862B is a same radial distance from alongitudinal axis of distal end surface 1866. Also, each drive dog1862A, 1862B is adjacent to the circumferential edge of distal endsurface 1866. The combination of radially equidistant drive dogs 1862A,1862B and of positioning of drive dogs 1862A, 1862B adjacent to thecircumferential edge allows drive dogs 1862A, 1862B to efficientlytransfer torque/motion to driven disk 964.

As illustrated in FIG. 18B, drive dogs 1862A, 1862B have mirror symmetrywith respect to a plane that includes x-axis 1871 and a longitudinalaxis (not shown) of intermediate disk 653. The longitudinal axis ofintermediate disk 653 is perpendicular to both axis 1870 and axis 1871at the intersection of axis 1870 and axis 1871.

Each of drive dogs 1862A, 1862B has mirror symmetry with respect to aplane that includes y-axis 1870 and the longitudinal axis (not shown).This plane bisects the drive dogs.

Drive dog 1862A is the same as drive dog 1862B and so only thecharacteristics of drive dog 1862A is considered in further detail. Thedescription of drive dog 1862A is directly applicable to drive dog 1862Band so the description is not repeated for drive dog 1862B.

The cylindrical sidewall portions of drive dog 1862A and the straightwall portions of drive dog 1862B are the same as the correspondingportions of drive dog 1652A, and so the description of these portions isnot repeated here. As shown in FIG. 18B, a lip 1862L extends radiallyoutward from the distal end of the second portion of drive dog 1862A.Two sidewalls 1862 s 2, 1862 s 4 are perpendicular to sidewall 1862 s 1and lip 1862A1 extends radially outward from sidewall 1862 s 1. Lip1862L is a retention feature that retains intermediate disk 653 inmovable body 651C.

Engagement structure 1863C, in this aspect, is an open three-dimensionalstructure. Open three-dimensional structure has mirror symmetry withrespect to a plane including the longitudinal axis of intermediate disk653 and axis 1871, in this aspect. Here, an open three-dimensionalstructure means a three-dimensional structure that does not have aclosed perimeter, i.e., there is an opening at which an outer sidesurface meets an inner side surface. In the example of FIG. 18D, theopen three-dimensional structure includes two parts—a generallythree-dimensional letter C-shaped structure 1863C and two walls 1863A,1863B. Again, here a generally three-dimensional letter C-shapedstructure is a three-dimensional structure that is perceived as athree-dimensional letter C-shaped structure by a person viewing thestructure.

Three-dimensional letter C-shaped structure 1863C has a height, a firstend 1863C1, and a second end 1863C2. The height of structure 1863Cextends distally from distal end surface 1866 of intermediate disk 653,which could be called a distal face of intermediate disk 653, to themost distal end surface or most distal edge of structure 1863C. Firstend 1863C1 and second end 1863C2 bound an opening of C-shaped structure1863C. Axis 1871, in this aspect, is equidistant from first end 1863C1and from second end 1863C2 and is a centerline of C-shaped structure1863C.

C-shaped structure 1863C is an example of an open three-dimensionalstructure that is a circular track. The circular track includes a firstcircumferential section having a first height, a first end, and a secondend, e.g., the body of the C-shaped structure. The circular track alsoincludes a second circumferential section extending between the firstand second ends of the first circumferential section, e.g., the gapbetween the ends of the C-shaped structure. The second circumferentialsection has a second height. The second height is less than the firstheight. A centerline of the circular tracks extends through a center ofthe circular track and is equidistance from the first and second ends.

Wall 1863A abuts first end 1863C1 and extends towards thecircumferential edge of distal end surface 1866. Wall 1863B abuts secondend 1863C2 and extends towards the circumferential edge of distal endsurface 1866. Wall 1863A and wall 1863B have a same height. The heightof wall 1863A and of wall 1863B extends distally from distal end surface1866 of intermediate disk 653 to the most distal end surface or mostdistal edge of wall 1863A and of wall 1863B. The height of walls 1863Aand 1863B is smaller than the height of C-shaped structure 1863C.

As illustrated in FIGS. 18A and 18B, the axis that bisects drive dogreceptacles 1852A, 1852B, i.e., x-axis 1871, is perpendicular to theaxis that bisects drive dogs 1862A, 1862B. When all the discs are matedas in disc stack 1400, the axis of allowed rotation for intermediatedisk 653 and driven disk 964 is 90 degrees to the axis of allowedrotation for intermediate disk 653 and drive output disk 545. Statedanother way, each of drive dog receptacles 1852A, 1852B of intermediatedisk 653 is positioned so that each of drive dog receptacles 1852A,1852B is bisected by a first plane. Each of drive dogs 1862A, 1862B ofintermediate disk 653 is positioned so that each of drive dogs 1862A,and 1862B is bisected by a second plane. The first plane isperpendicular to the second plane.

The coupling of the interfaces between intermediate disk 653 and driveoutput disk 545 forms a first joint, while the coupling of theinterfaces between intermediate disk 653 and driven disk 964 forms asecond joint. Together these two working joints accommodate angularmisalignment as the system rotates and transmits motion/torque. The twojoints act like a set of U-Joints.

FIG. 19A is an illustration of driven interface 980 on a proximal end ofdriven disk 964. Driven interface 980 includes an engagement receptacle,drive dog receptacles 1952A, 1952B, and a rotation disable element 1980.As explained more completely below, rotation disable element 1980includes a rotation locking mechanism 1981.

Drive dog receptacles 1952A, 1952B have mirror symmetry with respect toa plane that includes x-axis 1971 and a longitudinal axis (not shown) ofdriven disk 964. The longitudinal axis of driven disk 964 isperpendicular to the intersection of axis 1970 and axis 1971. Each ofdrive dog receptacles 1952A, 1952B has mirror symmetry with respect to aplane that includes y-axis 1970 and the longitudinal axis of driven disk964. This plane bisects the drive dog receptacles. Each drive dogreceptacle has an inner edge surface that is a same distance Rrcpt2 fromthe longitudinal axis of driven disk 964. Since drive dog receptacle1952A is the same as drive dog receptacle 1952B, only thecharacteristics of drive dog receptacle 1952B are considered in furtherdetail. The description of drive dog receptacle 1952B is directlyapplicable to drive dog receptacle 1952A and so the description is notrepeated for drive dog receptacle 1952A.

Drive dog receptacle 1952B can be bounded by four sides. Second andfourth sides are walls that are perpendicular to a first side. The thirdside is a wall that is perpendicular to the second and fourth sides.However, in this aspect, a first of four sides is missing and so isreferred to as an open first side. The use of an open sidewall isillustrative only and is not intended to be limiting. In some aspects,the first sidewall can be a solid sidewall.

Thus, in this aspect, drive dog receptacle 1952B is bounded by threewalls that each extends from an outer proximal edge surface 1956 ofdriven disk 964 to a bottom surface 1957 of drive dog receptacle 1952B.The third wall that is opposite to the open side is a straight wall 1952s 3 extending from outer proximal edge surface 1956 to bottom surface1957. The two opposing walls, second and fourth walls, have twoportions, straight wall portions 1952 s 2, 1952 s 4, and a sloped wallportion 1952 w 2, 1952 w 4.

Thus, drive dog receptacle 1952B is divided into a first portion 1952B1and a second portion 1952B2. First portion 1952B1 extends into drivendisk 964 from an outer proximal edge surface 1956 to second portion1952B2. Second portion 1952B2 extends further into driven disk 964 fromfirst portion 1952B1 to bottom surface 1957 of drive dog receptacle1952B. The other characteristics of drive dog receptacle 1952B are thesame as the characteristics described above for drive dog receptacle1852A and so that description is applicable to drive dog receptacle1953B and is not repeated here.

Engagement receptacle 1963, in this aspect, includes an openthree-dimensional groove formed in the proximal end of driven disk 964.The open three-dimensional groove extends distally into driven disk 964from outer proximal edge surface 1956. Here, an open three-dimensionalgroove means a three-dimensional groove that does not have closed innerand outer perimeters. In the example of FIG. 19A, the openthree-dimensional groove is a generally three-dimensional letterC-shaped groove 1963C that has a width and a depth.

Three-dimensional letter C-shaped groove 1963C has a first end 1963C1and a second end 1963C2. First end 1963C1 and second end 1963C2 areseparated from rotation disable element 1980 by a first gap 1963A and asecond gap 1963B, respectively.

In this aspect, rotation disable element 1980 includes a flexure 1980Fwith rotation locking mechanism 1981 at one end. In this aspect, flexure1980F extends radially outward from a center region of the proximal endof driven disk 964 towards the sidewall of driven disk 964. The centerregion is bounded by C-shaped groove 1963C. Rotation locking mechanism1981 extends in a distal direction from an end of flexure 1980F.Rotation locking mechanism 1981 forms part of a sidewall of disk 964.The most distal end of rotation locking mechanism 1981 is a tang, inthis aspect.

FIG. 19B is an illustration of a part of body 1985 of driven interfaceassembly 961. Body 1985 includes a driven disk receptacle 1986. Aplurality of gear teeth 1987 extend in the proximal direction from abottom surface of driven disk receptacle 1986. Body 1985 includes adriven disk receptacle 1986 for each driven disk 964 in plurality ofdriven disks 964P.

Shaft 1466 of transmission unit 965 has a proximal end that extends intodriven disk receptacle 1986. Driven disk 964 is mounted on the proximalend of shaft 1466 so that driven disk 964 is positioned in driven diskreceptacle 1986 and can rotate within driven disk receptacle 1986.

When surgical instrument 260 is first mounted in sterile adapterassembly 250, driven disk 964 in driven interface assembly 961 pushesintermediate disk 653 in sterile adapter assembly 250 proximallyrelative to movable body 651C so that the intermediate disk 653 canrotate freely, e.g., tab 1767 on intermediate disk 653 is movedproximally so that tab 1767 no long contacts hard stop 1761 asintermediate disk 653 rotates. Typically, when surgical instrument 260is first mounted in sterile adapter assembly 250, intermediate driveinterface 756 of intermediate disk 653 in sterile adapter assembly 250is not aligned with driven interface 980 of driven disk 964. Thus,intermediate disk 653 and driven disk 964 are not mated. FIG. 20Aillustrates a cut-away view of when intermediate disk 653 and drivendisk 964 are in partial contact, i.e., are partially coupled.

When intermediate disk 653 and driven disk 964 are put in contact andpartially coupled, C-shaped structure 1863C is partially inserted inC-shaped groove 1963C. However, wall 1863A is not aligned with gap 1963Aand wall 1863B is not aligned with gap 1963B. Thus, C-shaped structure1863C only goes into C-shaped groove 1963C until walls 1863A, 1863Bcontact proximal outer edge surface 1956 of driven disk 964.

A part of C-shaped structure 1863C rests on flexure 1980F and deflectsflexure 1980F in the distal direction. The deflection of flexure 1980Fmoves rotation-locking mechanism 1981 distally so that tang 1981Tengages teeth 1987 on the bottom surface of driven disk receptacle 1986.The engagement of tang 1981T with teeth 1987 prevents driven disk 964from rotating.

Thus, as driven disk 964 is held stationary and intermediate disk 653 isrotated, walls 1863A and 1863B become aligned with gap 1963A and gap1963B, respectively, and the preload force causes C-shaped structure1863C to insert completely into C-shaped groove 1963C and walls 1863Aand 1863B to insert into gap 1963A and gap 1963B, respectively. Also,each of the drive dogs is inserted into the corresponding drive dogreceptacle. Since C-shaped structure 1863C is no longer pushing onflexure 1980F, flexure 1980F returns to the undeflected state (FIG.20B). This disengages tang 1981T from teeth 1987 and so driven disk 964can rotate. Hence, driven disk 964 has coupled with intermediate disk653 so that torque is transferred to shaft 1466.

Flexure 1980F is illustrative only and is not intended to be limiting.For example, a spring-loaded pin could be included in the driven disk964 so that C-shaped structure 1863C depressed the pin untilintermediate disk 653 and driven disk 964 were coupled. The depressedpin could push on a flexure in the distal end of driven disk 964 thatincludes a tang on one end. The tang would engage teeth 1987 until theforce on the flexure was removed. Alternatively, the spring-loaded pincould engage teeth 1987 to prevent rotation.

After surgical instrument 260 is mounted on sterile adapter assembly 250and the intermediate disks are coupled with the driven disks,motion/torque can be transferred from drive unit assembly 541 totransmission unit in surgical instrument 260. However, as describedabove, under the first preload force that is supplied by the compressionof spring 1601, there is some backlash in disk stack 1400.

Under the first preload force, the coupling between intermediate disk653 and driven disk 964 and the coupling between drive output disk 545and intermediate disk 653 have a known non-zero backlash for torquelevels necessary to bring the two disks into alignment. However, forlower torque levels, the partial coupling between drive output disk 545and intermediate disk 653 has zero backlash. To reduce the backlash ofthe coupling between intermediate disk 653 and driven disk 964 and ofthe coupling between drive output disk 545 and intermediate disk 653 tozero for torque levels used in surgical procedures, the preload force ischanged from the first preload force to the second preload force usingpreload assembly 780.

FIG. 21 is a more detailed illustration of one aspect of insertionassembly 331. Insertion assembly 331 includes a frame 2110, amid-carriage 2120, and a distal carriage 2130. Mid-carriage 2120 rideson a ball screw 2111 in frame 2110. In one aspect, ball screw 2111 has a6 mm pitch and so is back drivable. Mid-carriage 2120 includes metalbelts 2121 that drive distal carriage 2130. Distal carriage 2130 isattached to instrument manipulator assembly housing 741 of instrumentmanipulator assembly 240. Distal carriage 2130 moves twice as far asmid-carriage 2120 in one aspect.

FIGS. 22A and 22B illustrate preload assembly 780 in greater detail. InFIGS. 22A and 22B, surgical instrument 260 is mounted in sterile adapterassembly 250. However, for ease of illustration, surgical instrument 260is not shown in FIGS. 22A and 22B. The distal end of surgical instrumentis, for example positioned at an entry to a channel in entry guide 270.

Initially, as shown in FIG. 22A, cam follower assembly 2283 in preloadassembly 780 is positioned in a valley in a preload track 2225 onmid-carriage 2120, e.g., is positioned at a first location on preloadtrack 2225. Preload track 2225 is mounted on mid-carriage 2120. Thevalley is located at a proximal end of preload track 2225. Cam followerassembly 2283 is rotatably connected to a first end of an arm 2282 inpreload assembly 780. A second end of arm 2282 is connected to a motorpack bracket 2281. Motor pack bracket 2281 is affixed to motor pack1541. Thus, arm 2282 is coupled to motor pack 1541. In FIGS. 22A and22B, instrument manipulator assembly housing 741 is transparent so thatthe features and elements within instrument manipulator assembly housing741 are visible. As indicated above, instrument manipulator assemblyhousing 741 is affixed to distal carriage 2130

At the first location, light preload spring 1601 in each drive outputassembly 543 has been compressed, and the first preload force is appliedto each disk in disk stack 1400. As surgical device assembly 300 ismoved distally a distance Zload by insertion assembly 331 from the firstlocation (FIG. 22A) to a second location (FIG. 22B) instrumentmanipulator assembly housing 741 is moved distance Zload.

Pivot pin 2284, on which cam follower assembly 2283 is rotatablymounted, is coupled to instrument manipulator assembly housing 741 ofinstrument manipulator assembly 240. Thus, as insertion assembly 331moves instrument manipulator assembly housing 741 distally a distanceZload, pivot pin 2284 moves cam follower assembly 2283 the same distanceZload. In one aspect distance Zload is 3.85 inches.

A wheel 2283W is rotatably attached to a first end of cam followerassembly 2283, and wheel 2283W rides on preload track 2225. Thus, as camfollower assembly 2283 moves distally, wheel 2283W follows the contourof preload track 2225. However the distance between preload track 2225and pivot point 2284 diminishes as cam follower assembly 2283 movesdistally. Consequently, as cam follower assembly 2283 rides up ramp2225R in preload track 2225, cam follower assembly 2283 rotates from afirst position illustrated in FIG. 22A to a second position asillustrated in FIG. 22B and moves motor pack 1541 a distance that isgreater than the distance traveled by instrument manipulator assemblyhousing 741. Thus, the rotation of cam follower assembly 2283 displacesmotor pack 1541 a predetermined distance distally relative to instrumentmanipulator assembly housing 741.

To understand the forces acting on cam follower assembly 2283, considerthe free body force diagram in FIG. 22C. FIG. 22C illustrates a portionof cam follower assembly 2283 and a portion of preload track 2225. Ascam follower assembly 2283 moves wheel 2283W up ramp 2225R of preloadtrack 2225, preload track 2225 exerts a wheel force F_wheel on preloadtrack 2225. Wheel force F_wheel is perpendicular to preload track 2225.Force F_wheel is made up of two perpendicular forces—a retraction forceF_retract and a longitudinal force F_long. Retraction force F_retract isa force that the user would apply in the distal direction to movesurgical device assembly 300 distally. Alternatively, part or all ofthis force could be applied by the motor so that the user does not needto exert the full force.

As cam follower assembly 2283 moves from the first location to thesecond location, a force proportional to longitudinal force F_long istransferred to arm 2282 by cam follower assembly 2283. The forceproportional of longitudinal force F_long is applied on motor pack 1541through arm 2282 and motor pack bracket 2281.

Thus, two acts are performed by cam follower assembly 2282 as camfollower assembly 2283 travels along track 2225. As cam followerassembly 2283 moves up ramp 2225R and rotates, the rotation of camfollower assembly 2283 pushes motor pack distally a distance greaterthan distance Zload, e.g., motor pack 1541 moves a distance (Zload+Δ).In addition, as cam follower assembly 2283 moves up ramp 2283W, camfollower assembly 2283 transfers a force proportional of longitudinalforce F_long to motor pack 1541, which in turn compresses the first andsecond springs 1601, 1602 so that second preload force is asserted ondrive output disk 545. The second preload force is a combination of theforces provided by compressed spring 1601, 1602. A force provided bycompressed spring 1602 is larger than a force provided by compressedspring 1601. The second preload force asserted on drive output disk 545is applied to each of the other disks in disk stack 1400. As describedabove, in one aspect, the second preload force is 3.0 Lbf. Of course,this is true only when a surgical instrument has been installed, becauseotherwise the springs do not compress.

FIGS. 22D and 22E shows that motor pack 1541 has moved an additionaldistance A relative to the top of instrument manipulator assemblyhousing 741 that moved distance Zload. In one aspect, distance Δ is0.212 inches. In this aspect, FIGS. 22D and 22E show that distance theproximal end of arm 2282 moves as cam follower assembly 2283 rotates isdistance A. This is illustrative only and is not intended to belimiting.

In other implementations, cam follower assembly 2283 could havedifferent length moment arms 2283M1 and 2283M2 (see FIG. 23) so thatwhen wheel 2283W traverses ramp 2225R having a height Δ, arm 2282 andconsequently motor pack 1541 is moved a distance larger than distance Δ,or alternatively could have different length moment arms 2283M1 and2283M2 (see FIG. 23) so that when wheel 2283W traverses ramp 2225Rhaving a height Δ, arm 2282 and consequently motor pack 1541 is moved adistance smaller than distance Δ. Finally, FIGS. 22D illustrates that aramp 2225R has a height Δ, e.g., wheel 2283W is displaced a distance Δin a direction perpendicular to track 2225 as wheel 2283W moves from thefirst position to the second position.

FIG. 22F is an illustration of one aspect of preload track 2225. Oneexample of dimensions for preload track 2225 is given in Table 2.

TABLE 2 REFERENCE NUMBER DIMENSION Home 0 inches P1 0.05 inches P2 0.33inches P3 1.14 inches P4 1.92 inches R2 1.80 inches (radius) R3 5.00inches (radius) A3 171 degrees Δ 0.212 inches

Preload track 2225 is configured to smoothly ramp the preload force fromthe first preload force to the second preload force. FIG. 22G is a graphof the retraction force as preload assembly 780 moves distally from thefirst location to the second location on preload track 2225. Curve 2280gives the retraction force at each insertion distance. The retractionforce acts on the instrument manipulator assembly housing 741 in theproximal direction.

In this example, the first position is an insertion distance of 0.0inches and the second position is an insertion distance of 3.85 inches.The retraction force increases about linearly from 0.0 to about 0.6inches, then continues to increase linearly at a reduced slope fromabout 0.6 to 2.2 inches. From about 2.2 to 2.6 inches, the forceincreases and peaks, then tapers to zero force at about 3.85 inches. Atan insertion distance of 3.85 inches, the second preload force of 2.3Lbf is reached. At an insertion distance of 3.85 inches, the secondpreload spring is compressed to its maximum value in this design, and soprovides no additional resistance to distal motion. In this example, theinstrument tip protrudes from the cannula at an insertion depth of 4.8inches or larger. Thus, disk stack 1400 is fully preloaded and thebacklash effectively reduced to zero before the instrument tip exits thecannula.

With curve 2280, a track is machined that provides this retraction forceversus insertion profile. The machining creates a preload track profilethat smoothly ramps the preload force according to curve 2280. Curve2280 is illustrative only and is not intended to be limiting. In view ofthis disclosure, one knowledgeable in the field can create a retractionforce versus insertion distance for a particular preload spring assemblyand a particular cannula and surgical instrument.

FIG. 23 is a more detailed illustration of preload assembly 780. Arm2282 has a first end 2882A rotatably connected to a first end 2283A ofan L-shaped body 2283B of cam follower assembly 2283. A second end 2282Bof arm 2282 is connected to motor pack bracket 2281. Motor pack bracket2281 is affixed to motor pack 1541.

In this aspect, first moment arm 2283M1 is perpendicular to secondmoment arm 2283M2 at pivot pin 2284 and have a same length. Thus, inthis aspect, longitudinal force F_long is applied to motor pack 1541However, in other aspects, the two moment arms may not be perpendicular.If the moment arms are not perpendicular, or if the moment arms havedifferent lengths, the force applied to motor pack 1541 is proportionalto longitudinal force F_long. In each aspect, the shape of body 2283B isselected to accommodate the two moment arms and to provide the necessarystrength to rotate and transfer the longitudinal force to the motorpack.

Second end 2283C of L-shaped body 2283B is rotatably connected to wheel2283W. Wheel 2283W rides on preload track 2225. A vertex of L-shapedbody 2283B is rotatably connected to pivot pin 2284. Pivot pin 2284 isfixedly attached to instrument manipulator assembly housing 741 ofinstrument manipulator assembly 240. First moment arm 2283M1 of preloadassembly 740 extends from the center of rotation of wheel 2283W to acenter of rotation of vertex of L-shaped body 2283B. Second moment arm2283M2 of preload assembly 740 extends from the center of rotation offirst end 2282A of arm 2282 to a center of rotation of vertex ofL-shaped body 2283B. Since the distance between pivot pin 2284 and track2225 is fixed, as wheel 2283W moves distally up the ramp, cam followerassembly 2283 rotates as indicated in FIG. 22B and so motor pack 1541 isdisplaced relative to instrument manipulator assembly housing 741 andconsequently longitudinal force F_long is applied on spring assembliesin motor pack 1541.

In FIG. 23, preload assembly 780 also includes a preload releasemechanism. The preload release mechanism includes a preload releasebutton 2382, a preload release lever 2385, a preload engagement arm2386, and a return spring (not shown, but see FIGS. 4A to 4H). Preloadrelease button 2382 is an example of preload release button 482. Alsonot shown in FIG. 23 is a torsional spring, concentric with pin 2388,which exerts a clockwise torque on preload release lever 2385 (clockwiserelative to FIG. 23). This is necessary to keep preload release lever2385 and preload release button 2382 in the unreleased position (shown),unless release button 2382 is pressed.

A first end, a proximal end, of preload engagement arm 2386 is rotatablycoupled to pivot pin 2284. A rolling pin 2386P is mounted in a secondend, a distal end of preload engagement arm 2386. Proximal to rollingpin 2386P in the second end of preload engagement arm 2386 is a preloadengagement surface 2386S. In this aspect, preload engagement surface2386S is perpendicular to the flat portion of preload track 2225.Preload engagement arm 2386 is coupled to a linear rail.

A hook on a first end, a proximal end, of preload release lever 2385 isengaged with rolling pin 2386P in the second end of preload engagementarm 2386. Preload release button 2382 is coupled to, e.g., is in contactwith, a second end, a distal end, of preload release lever 2385. Betweenthe first and second ends of preload release lever 2385, preload releaselever is rotatably mounted on another pivot pin 2388, which functions asa fulcrum for preload release lever 2385.

In this example, preload release lever 2385 is a Class 1 lever becausethe fulcrum is between the effort (the forces supplied by preloadrelease button 2382) and the load (the coupling between the hook androlling pin 2386P). While in this example, preload release lever 2385 isimplemented as a Class 1 lever, this is illustrative only and is notintended to be limiting. In other aspects, a Class 2 lever or a Class 3lever could be used. For a Class 2 lever, the load is between thefulcrum and the effort, and for a Class 3 lever, the effort is betweenthe fulcrum and the load.

If insertion assembly 331 jams, the high preload force must be releasedso that surgical instrument 260 can be removed. To remove surgicalinstrument 260, a user pushes preload release button 2382 (FIG. 24A). Inresponse to the force provided by the user, preload release button 2382applies a force to the second end of preload release lever 2385. Theforce on the second end preload release lever 2385 causes preloadrelease lever 2385 to rotate about pivot pin 2388 and disengage the hookon the second end of preload release lever 2385 from rolling pin 2386Pthat is mounted in the second end of preload engagement arm 2386.

Recall that the return spring is mounted between instrument manipulatorassembly housing 741 and motor pack 1541 and is stretched when the highpreload force is applied. Consequently, when preload release lever 2385disengages from preload engagement arm 2386, the return spring retractsmotor pack 1541 to a fully withdrawn position.

At the fully withdrawn position, there is no preload force, and driveoutput disk 545 is disengaged from intermediate disk 653. In addition, arelease latch inhibit stop and a plurality of hard stops 2437 arewithdrawn so that both instrument sterile adapter assembly 250 andsurgical instrument 260 can be dismounted. If the distal end of surgicalinstrument 260 is not straight, as a person withdraws the surgicalinstrument, the cannula forces the distal end of surgical instrument 260to straighten because the disk stack without the preload force andwithout drive output disk 545 engaged is back drivable.

FIG. 24B is an illustration of one implementation of the automaticpreload reset mechanism in preload assembly 780. When sterile adapterassembly 250 is mounted on instrument manipulator assembly 240,instrument manipulator assembly 240 sends a signal to controller 290indicating the presence of sterile adapter assembly 250. In response tothe signal, controller 290 activates a motor that moves instrumentmanipulator assembly 240 proximally.

Instrument manipulator assembly housing 741 moves proximally twice asfast as preload engagement ridge 2326 on preload track 2225. This isbecause distal carriage 2130 moves twice as far as mid carriage 2120. Inthis aspect, preload engagement ridge 2326 extends from a distal portionof preload track 2225.

Thus, as instrument manipulator assembly housing 741 moves proximally,preload engagement ridge 2326 moves proximally at half the speed ofpreload engagement arm 2386 and instrument manipulator assembly housing741. Thus, surface 2386S of preload engagement arm 2386 engages preloadengagement ridge 2326 on preload track 2225 as instrument manipulatorassembly housing 741 moves proximally. As instrument manipulatorassembly housing 741 continues to move proximally, preload engagementridge 2326 exerts a longitudinal force in the distal direction onsurface 2386S of preload engagement arm 2386. This causes cam followerassembly 2283 to apply a longitudinal force on motor pack 1541 asdescribed above. As motor pack 1541 is moved by the longitudinal forcein the proximal direction beyond location Preload_1, the hook on preloadrelease lever 2385 (not visible in FIG. 24B) engages rolling pin 2386P.After the engagement of the hook on preload release lever 2385 onrolling pin 2386P, instrument manipulator assembly housing 741 is moveddistally so that motor pack 1541 is at location Preload_1. Theapplication of the preload force is automatic upon mounting of sterileadapter assembly 250, in this aspect, and so a preload force ismaintained on drive output disk 545 after mounting of sterile adapterassembly 250.

Note that in FIGS. 23, 24A, and 24B only the elements necessary tounderstand the release mechanism are illustrated. The actualconfiguration associated with FIGS. 23, 24A, and 24B includes all theelements shown and described with respect to FIG. 22A.

FIG. 25 is a cut-away view of a portion of surgical device assembly 300that illustrates a surgical instrument removal lockout apparatus. Thesurgical instrument removal lockout apparatus includes the preloadmechanism that applies a preload force on disk stack 1400, a pluralityof hard stops 2437, and a plurality of hard stop receptacles 1757.Plurality of hard stops 2437 are an example of plurality of hard stops437.

Each of plurality of hard stops 2437 extends in a distal direction froma distal face of motor pack 1541. As illustrated in FIG. 17A, each ofplurality of hard stop receptacles 1757 extends from a proximal face ofmoveable body 651C of sterile adapter assembly 250 in a distal directioninto moveable body 651C.

When sterile adapter 250 is mounted on surgical instrument manipulatorassembly 240 and the preload force is automatically engaged as describedabove, moveable body 251 is at the most distal position within sterileadapter frame 651 of sterile adapter assembly 250. In this position,plurality of hard stops 2437 is not in plurality of hard stopreceptacles 1757, and movable body 651C is free to move within sterileadapter frame 651.

Hence, surgical instrument 260 can be mounted in sterile adapterassembly 250 as described above. However, when the second preload forceis applied on output drive assemblies 543 and the spring assembly isfully compressed, plurality of hard stops 2437 extend into plurality ofhard stop receptacles 1757, and plurality of hard stops 2437 preventsmoveable body 651C from moving in the proximal direction. Removal ofsurgical instrument 260 moves movable body 651C in the proximaldirection. Hence, if the second preload force is applied to motor pack1541, plurality of hard stops 2437 prevents moveable body 651C frommoving in the proximal direction, and consequently removal of surgicalinstrument 260 is inhibited.

The use of plurality of hard stop receptacles 1757 is illustrative onlyand is not intended to be limiting. In another aspect, plurality of hardstop receptacles 1757 is not used. Instead, plurality of hard stops 2437contact a proximal surface of moveable body 651C and prevent movement ofmoveable body 651C in the proximal direction.

Hence, a surgical instrument manipulator assembly 240 includes aninstrument manipulator assembly housing 741, sometimes referred to ashousing 741, and a motor pack 1541. Motor pack 1541 is movably coupledto housing 741. A plurality of hard stops 2437 are mounted in a distalend of motor pack 1541. Plurality of hard stops 2437 can be positionedin at least a first position and a second position relative to housing741 of the surgical instrument manipulator assembly 240. When pluralityof hard stops 2437 is in the first position, a surgical instrument 260can be coupled to and decoupled from instrument manipulator assembly240. When plurality of hard stops 2437 is in the second position,surgical instrument 260 cannot be decoupled from instrument manipulatorassembly 240.

FIG. 26A is a more detailed cut-away illustration of sterile adapterrelease latch 2635. Sterile adapter release latch 2635 is an example ofone aspect of release latch 435. Lip 654 on one end of sterile adapterframe 651 is engaged by a lip 2635L extending from a distal end ofsterile adapter release latch 2635. Sterile adapter release latch 2635is mounted in a wall of instrument manipulator assembly housing 741 sothat sterile adapter release latch 2635 can pivot to engage with anddisengage from sterile adapter frame 651 of sterile adapter assembly250. In one aspect, the pivotal connection of sterile adapter releaselatch 2635 to the frame is spring loaded is so that the steady positionof latch 2635 is in the engaged position. A latch pin 2635P is coupledto a proximal portion of sterile adapter release latch 2635. When motorpack 1541 is fully withdrawn at location Home, e.g., when no preloadforce is exerted on motor pack 1541, latch pin 2635P does not preventsterile adapter release latch 2635 from pivoting to engage with anddisengage from sterile adapter frame 651.

When sterile adapter assembly 250 is mounted on instrument manipulatorassembly 240, the automatic preload reset mechanism, as described above,exerts a preload force, e.g., a light preload force, on motor pack 1541when motor pack 1541 is moved to location Preload_1 by the preloadengagement mechanism. When motor pack 1541 is moved to locationPreload_1, release latch inhibit stop 2638 that is mounted to motor pack1541 also is moved distally.

When motor pack 1541 is at location Preload_1, if the proximal end ofsterile adapter release latch 2635 is pushed, latch pin 2635P contactsrelease latch inhibit stop 2638, which prevents sterile adapter releaselatch 2635 from pivoting to disengage from sterile adapter frame 651.Thus, when the light preload force is asserted on motor pack 1541,removal of sterile adapter assembly 250 is inhibited.

FIG. 26A illustrates a potential problem if the automatic preload resetmechanism is energized, while sterile adapter release latch 2635 isdepressed. As release latch inhibit stop 2638 moves distally, releaselatch inhibit stop 2638 would hit latch pin 2635P if sterile adapterrelease latch 2635 were not released. This potentially could damagelatch pin 2635P, e.g., bend latch pin 2635P, so that the sterile adapterremoval inhibit mechanism would not work properly. Thus, in one aspectlatch pin 2636P (FIG. 26B) is pivotally connected to a proximal portionof sterile adapter release latch 2635, and the connection isspring-loaded by spring 2634. Thus, if sterile adapter release latch2635 is depressed and the automatic preload reset mechanism isenergized, upon latch inhibit stop 2638 hitting latch pin 2635P, latchpin 2635P pivots and so is not damaged. When sterile adapter releaselatch 2635 is released, spring 2634 causes latch pin 2633P to return toits original position.

In some of the above examples, the terms “proximal” or “proximally” areused in a general way to describe an object or element which is closerto a manipulator arm base along a kinematic chain of system movement orfarther away from a remote center of motion (or a surgical site) alongthe kinematic chain of system movement. Similarly, the terms “distal” or“distally” are used in a general way to describe an object or elementwhich is farther away from the manipulator arm base along the kinematicchain of system movement or closer to the remote center of motion (or asurgical site) along the kinematic chain of system movement.

As used herein, “first,” “second,” “third,” “fourth,” etc. areadjectives used to distinguish between different components or elements.Thus, “first,” “second,” “third,” “fourth,” etc. are not intended toimply any ordering of the components or elements.

The above description and the accompanying drawings that illustrateaspects and embodiments of the present inventions should not be taken aslimiting—the claims define the protected inventions. Various mechanical,compositional, structural, electrical, and operational changes may bemade without departing from the spirit and scope of this description andthe claims. In some instances, well-known circuits, structures, andtechniques have not been shown or described in detail to avoid obscuringthe invention.

Further, this description's terminology is not intended to limit theinvention. For example, spatially relative terms—such as “beneath”,“below”, “lower”, “above”, “upper”, “proximal”, “distal”, and thelike—may be used to describe one element's or feature's relationship toanother element or feature as illustrated in the figures. Thesespatially relative terms are intended to encompass different positions(i.e., locations) and orientations (i.e., rotational placements) of thedevice in use or operation in addition to the position and orientationshown in the figures. For example, if the device in the figures isturned over, elements described as “below” or “beneath” other elementsor features would then be “above” or “over” the other elements orfeatures. Thus, the exemplary term “below” can encompass both positionsand orientations of above and below. The device may be otherwiseoriented (rotated 90 degrees or at other orientations) and the spatiallyrelative descriptors used herein interpreted accordingly. Likewise,descriptions of movement along and around various axes include variousspecial device positions and orientations.

The singular forms “a”, “an”, and “the” are intended to include theplural forms as well, unless the context indicates otherwise. The terms“comprises”, “comprising”, “includes”, and the like specify the presenceof stated features, steps, operations, elements, and/or components butdo not preclude the presence or addition of one or more other features,steps, operations, elements, components, and/or groups. Componentsdescribed as coupled may be electrically or mechanically directlycoupled, or they may be indirectly coupled via one or more intermediatecomponents.

All examples and illustrative references are non-limiting and should notbe used to limit the claims to specific implementations and embodimentsdescribed herein and their equivalents. Any headings are solely forformatting and should not be used to limit the subject matter in anyway, because text under one heading may cross reference or apply to textunder one or more headings. Finally, in view of this disclosure,particular features described in relation to one aspect or embodimentmay be applied to other disclosed aspects or embodiments of theinvention, even though not specifically shown in the drawings ordescribed in the text.

We claim:
 1. An apparatus comprising: a surgical device interfaceelement comprising a first body structure and an intermediate diskrotatably mounted in the first body structure; the intermediate diskcomprising a driven interface and a drive interface, the driveninterface being configured to interface with a drive output disk of aninstrument manipulator assembly, and the drive interface being oppositethe driven interface; one of the driven interface or the drive interfacecomprising a drive dog receptacle extending into the intermediate disk,the drive dog receptacle comprising one or more sloped surfaces; and theother of the driven interface or the drive interface comprising a drivedog extending from the intermediate disk.
 2. The apparatus of claim 1,wherein: the drive dog receptacle comprises a first portion, a secondportion, and a third portion; the first portion comprises opposedsidewalls extending from an outer surface into the intermediate disk;the second portion comprises a bottom surface of the drive dogreceptacle; and the third portion extends from the first portion to thesecond portion, the one or more sloped surfaces being disposed on thethird portion.
 3. The apparatus of claim 2, wherein the one of the oneor more sloped surfaces comprises a portion of a side surface of awedge.
 4. The apparatus of claim 1, wherein: the drive dog receptaclecomprises a first edge surface and a second edge surface; the first edgesurface is positioned a first distance from a longitudinal axis of theintermediate disk; and the second edge surface is opposite the firstedge surface.
 5. The apparatus of claim 1, further comprising: theinstrument manipulator assembly; wherein the surgical device interfaceelement is mounted on the instrument manipulator assembly.
 6. Theapparatus of claim 5, wherein: the drive output disk of the instrumentmanipulator assembly comprises a manipulator drive interface; themanipulator drive interface is coupled with the driven interface of theintermediate disk to make a coupling between the intermediate disk andthe drive output disk; and the coupling between the intermediate diskand the drive output disk comprises zero backlash on the condition thata predetermined preload force is applied to urge the intermediate diskand the drive output disk together.
 7. The apparatus of claim 1,wherein: the drive dog comprises a first portion and a second portion;the first portion comprises straight sidewalls; and the second portionextends from the first portion and comprises curved sidewalls.
 8. Theapparatus of claim 7, wherein each of the curved sidewalls comprises aportion of a circular section.
 9. The apparatus of claim 1, wherein: thesurgical device interface element further comprises a second bodystructure; and the first body structure is movably mounted in the secondbody structure.
 10. The apparatus of claim 9, wherein the second bodystructure comprises a skid plate.
 11. The apparatus of claim 1, wherein:the surgical device interface element further comprises a second bodystructure; and the first body structure is movably mounted in the secondbody structure.
 12. An apparatus comprising: a surgical device interfaceelement comprising a first body structure and an intermediate diskrotatably mounted in the first body structure; the intermediate diskcomprising a driven interface and a drive interface, the driveninterface being configured to interface with a drive output disk of aninstrument manipulator assembly, and the drive interface being oppositethe driven interface; one of the driven interface or the drive interfacecomprising a drive dog receptacle extending into the intermediate disk;and the other of the driven interface or the drive interface comprisinga drive dog extending from the intermediate disk, the drive dogcomprising a proximal portion and a distal portion, and the distalportion of the drive dog comprising one or more curved sidewalls. 13.The apparatus of claim 12, wherein: the drive dog receptacle comprises afirst portion, a second portion, and a third portion; the first portioncomprises opposed sidewalls extending from an outer surface into theintermediate disk; the second portion comprises a bottom surface of thedrive dog receptacle; and the third portion extends from the firstportion to the second portion, the third portion comprising one or moresloped portion.
 14. The apparatus of claim 13, wherein the one or moresloped portion comprises a portion of a side surface of a wedge.
 15. Theapparatus of claim 12, wherein: the drive dog receptacle comprises afirst edge surface and a second edge surface; the first edge surface ispositioned a first distance from a longitudinal axis of the intermediatedisk; and the second edge surface is opposite the first edge surface.16. The apparatus of claim 12, further comprising: the instrumentmanipulator assembly; wherein the surgical device interface element ismounted on the instrument manipulator assembly.
 17. The apparatus ofclaim 16, wherein: the drive output disk of the instrument manipulatorassembly comprises a manipulator drive interface; the manipulator driveinterface is coupled with the driven interface of the intermediate diskto make a coupling between the intermediate disk and the drive outputdisk; and the coupling between the intermediate disk and the driveoutput disk comprises zero backlash on the condition that apredetermined preload force is applied to urge the intermediate disk andthe drive output disk together.
 18. The apparatus of claim 12, wherein:the proximal portion of the drive dog comprises straight sidewalls; andthe distal portion of the drive dog extends from the proximal portion,the one or more curved sidewalls being disposed on the distal portion.19. The apparatus of claim 18, wherein the one or more curved sidewallscomprises a portion of a circular section.
 20. An apparatus comprising:a surgical device interface element comprising a first body structureand an intermediate disk rotatably mounted in the first body structure;the intermediate disk comprising a distal portion and a proximalportion, the intermediate disk being configured to interface with adrive output disk of an instrument manipulator assembly and a drivendisk of an instrument; the proximal portion of the intermediate diskcomprising a driven means for engaging the drive output disk of theinstrument manipulator assembly; and the distal portion comprising adriving means for engaging the driven disk of the instrument.